How do I tell what type of PDF form I have?

Open the PDF and try to click a field. If a cursor blinks and you can type, it is a fillable AcroForm (or sometimes XFA — see below). If the field looks fillable but Acrobat says "this form contains XFA forms which may not be supported by your reader", it is XFA. If the field looks fillable but nothing happens when you click, it is a flat form designed for printing-and-handwriting. If the page is an image (zoom in and the text turns into pixels rather than crisp vectors), it is a scan. The ScoutMyTool tool runs this diagnosis automatically: drop the file, get a verdict with the count of each kind of field.

What is the difference between AcroForm and XFA?

AcroForm is the original PDF form mechanism, defined in PDF 1.2 (1996) and standardised in ISO 32000-1. It is supported by every modern PDF reader — Acrobat, Preview, Foxit, browser-built-in readers. XFA is an Adobe-proprietary XML-based form layer added in PDF 1.5 (2003), deprecated by the ISO committee for PDF 2.0 in 2017. XFA forms fill correctly only in Acrobat; other readers either show a static rendering or a "must open in Acrobat" warning. For form authoring, always use AcroForm — that is what ScoutMyTool produces.

My form looks fillable in Acrobat but my colleague says the fields are empty when they open it. Why?

Either (a) the form is XFA and they are using a non-Acrobat reader — the XFA layer does not render in other readers, leaving the fields empty; or (b) the form is AcroForm but they have a very old reader that does not implement AcroForm appearance streams. (a) is far more common. The fix: convert XFA to AcroForm. Acrobat Pro has a Preflight option for this; the ScoutMyTool form-rebuild tool does the same in the browser.

I have a flat form (the kind you have to print). Can I make it fillable?

Yes — that is exactly what the Fillable PDF tool does. Drop the flat form, run auto-detect (the tool spots underline blanks, checkbox squares, signature lines), add any missing fields manually, and download a fillable version. See the "How to make a fillable PDF form" article for the full workflow.

My form is a scan. Can I OCR it AND add fillable fields?

Yes, two passes. First, run OCR via the PDF OCR tool — this adds a searchable text layer over the scan. Then run the Fillable PDF tool with auto-detect — it spots field locations from the image and adds the AcroForm fields on top. The result is a fully searchable, fully fillable PDF whose visible content is the original scan. The OCR pass is important for accessibility and downstream search; the field pass is what makes it interactive.

Is my PDF uploaded to your servers during form analysis?

No. The form-type diagnostic runs entirely in your browser. The PDF is loaded into a sandboxed memory buffer, the page tree and AcroForm dictionary are parsed, the diagnosis is computed locally. Verify in DevTools Network — zero outbound requests. Important when the form contains personal data (intake forms, tax forms, HR forms) and the file should not leave your device.

Can I extract data from filled-in forms (bulk export to CSV)?

Yes, for AcroForms. The PDF Form Extract Data tool walks each AcroForm field in the input PDFs and writes their values to a CSV (one row per file, one column per field name). Useful when you have collected 50 filled forms back from respondents and need the data in a spreadsheet without manually retyping. XFA forms do not work with this — convert to AcroForm first. Scanned filled-in forms cannot be bulk-extracted; they require OCR + per-field reading, which is a much more error-prone operation.

PDF Form Types: Fillable vs Flat vs Scanned

6 min read

PDF forms — fillable vs flat vs scanned (which type do you have?)

By ScoutMyTool Editorial Team · Last updated: 2026-05-20

After working with hundreds of users on form-handling workflows, the same diagnostic confusion comes up every week: "I have this PDF form, why doesn't it fill in my browser?". The answer is almost always that the form is a different type from what the user assumes. There are five distinct kinds of PDF "form" in circulation, with different tools, different fill experiences, and different bulk-extract paths. Below is the diagnostic to identify which kind you have, with the workflow for each.

The five form types in one table

Type	How to identify	How to fill it	Bulk extract
AcroForm (modern fillable)	Click any field — cursor blinks, you can type	Use PDF Form Filler	Bulk-extract works (CSV)
XFA (Adobe legacy fillable)	Click field — Acrobat fills; other readers show "open in Acrobat" warning	Convert to AcroForm first	Convert first, then bulk-extract
Flat (designed for print + handwrite)	Field looks fillable but cursor never blinks	Use Fillable PDF tool to add AcroForm fields	Add fields first, then bulk-extract
Scanned (image-only)	Zoom in — text is pixelated, not crisp	OCR first, then add AcroForm fields	OCR + add fields, then bulk-extract
Hybrid (flat with some AcroForm fields)	Some fields blink, others do not	Add fields to the flat regions; preserve existing AcroForm	Bulk-extract works after adding missing fields

Step-by-step: identify the form type, then act

The ScoutMyTool form-type diagnostic lives at scoutmytool.com/pdf/pdf-form-list-fields. Runs client-side — no upload, no signup, no quota.

Drop your form. The tool parses the file and produces a diagnostic report: count of AcroForm fields, count of XFA fields, presence of scanned image content, presence of flat-but-marked-up regions.
If AcroForm count > 0 and no XFA.You have a modern fillable form. Use the PDF Form Filler to fill it; flatten after filling if you need the answers locked.
If XFA count > 0. The form is XFA. Convert to AcroForm first via the convert mode. After conversion, the diagnostic re-runs and should report AcroForm fields with no XFA.
If counts are zero and the page has crisp text. The form is flat — designed for printing and handwriting. Use the Fillable PDF tool with auto-detect to add AcroForm fields over the flat layout.
If counts are zero and the page is an image. The form is a scan. Run OCR first via PDF OCR, then add AcroForm fields. Both passes are client-side.
If hybrid (some AcroForm + some flat).Common for older government forms partially updated. Add missing fields to the flat regions; the existing AcroForm fields are preserved untouched.
After filling: bulk-extract the answers.When you have 50+ filled forms back from respondents, use PDF Form Extract Data to write all answers to a single CSV.

Why so many different types?

Three reasons, layered historically:

PDF was originally print-replacement (1993).The earliest PDFs were flat — designed to look like paper. Forms were drawn graphically; filling meant printing and handwriting. Many older government / healthcare forms still circulate in this format.
AcroForms added interactivity (1996).PDF 1.2 introduced the AcroForm dictionary — text inputs, checkboxes, radios, dropdowns. Every modern PDF reader supports them. This is the modern standard.
XFA was Adobe's attempt to do "more" (2003). XML-based, more programmable, but proprietary. Never gained cross-reader support and is deprecated in PDF 2.0¹. Still encountered in older government and financial forms; convert to AcroForm on intake.

And separately: scanned forms entered circulation in the 1990s–2000s when many institutions digitised paper archives without OCR. These remain in circulation indefinitely because rescanning is rarely worth the effort — the workflow is to OCR + add fields on demand.

Frequently asked questions

How do I tell what type of PDF form I have?: Open the PDF and try to click a field. If a cursor blinks and you can type, it is a fillable AcroForm (or sometimes XFA — see below). If the field looks fillable but Acrobat says "this form contains XFA forms which may not be supported by your reader", it is XFA. If the field looks fillable but nothing happens when you click, it is a flat form designed for printing-and-handwriting. If the page is an image (zoom in and the text turns into pixels rather than crisp vectors), it is a scan. The ScoutMyTool tool runs this diagnosis automatically: drop the file, get a verdict with the count of each kind of field.
What is the difference between AcroForm and XFA?: AcroForm is the original PDF form mechanism, defined in PDF 1.2 (1996) and standardised in ISO 32000-1. It is supported by every modern PDF reader — Acrobat, Preview, Foxit, browser-built-in readers. XFA is an Adobe-proprietary XML-based form layer added in PDF 1.5 (2003), deprecated by the ISO committee for PDF 2.0 in 2017. XFA forms fill correctly only in Acrobat; other readers either show a static rendering or a "must open in Acrobat" warning. For form authoring, always use AcroForm — that is what ScoutMyTool produces.
My form looks fillable in Acrobat but my colleague says the fields are empty when they open it. Why?: Either (a) the form is XFA and they are using a non-Acrobat reader — the XFA layer does not render in other readers, leaving the fields empty; or (b) the form is AcroForm but they have a very old reader that does not implement AcroForm appearance streams. (a) is far more common. The fix: convert XFA to AcroForm. Acrobat Pro has a Preflight option for this; the ScoutMyTool form-rebuild tool does the same in the browser.
I have a flat form (the kind you have to print). Can I make it fillable?: Yes — that is exactly what the Fillable PDF tool does. Drop the flat form, run auto-detect (the tool spots underline blanks, checkbox squares, signature lines), add any missing fields manually, and download a fillable version. See the "How to make a fillable PDF form" article for the full workflow.
My form is a scan. Can I OCR it AND add fillable fields?: Yes, two passes. First, run OCR via the PDF OCR tool — this adds a searchable text layer over the scan. Then run the Fillable PDF tool with auto-detect — it spots field locations from the image and adds the AcroForm fields on top. The result is a fully searchable, fully fillable PDF whose visible content is the original scan. The OCR pass is important for accessibility and downstream search; the field pass is what makes it interactive.
Is my PDF uploaded to your servers during form analysis?: No. The form-type diagnostic runs entirely in your browser. The PDF is loaded into a sandboxed memory buffer, the page tree and AcroForm dictionary are parsed, the diagnosis is computed locally. Verify in DevTools Network — zero outbound requests. Important when the form contains personal data (intake forms, tax forms, HR forms) and the file should not leave your device.
Can I extract data from filled-in forms (bulk export to CSV)?: Yes, for AcroForms. The PDF Form Extract Data tool walks each AcroForm field in the input PDFs and writes their values to a CSV (one row per file, one column per field name). Useful when you have collected 50 filled forms back from respondents and need the data in a spreadsheet without manually retyping. XFA forms do not work with this — convert to AcroForm first. Scanned filled-in forms cannot be bulk-extracted; they require OCR + per-field reading, which is a much more error-prone operation.

Identify your PDF form type now — free, no signup

Diagnoses AcroForm / XFA / flat / scanned / hybrid in one drop. Runs entirely in your browser.

Open the form type diagnostic at scoutmytool.com/pdf/pdf-form-list-fields →