How to make a fillable PDF form (free, no Acrobat)

Step-by-step: turn a static PDF into a fillable form

The ScoutMyTool tool lives at scoutmytool.com/pdf/fillable-pdf. Runs client-side via pdf-lib — no upload, no signup, no quota.

1. Drop your source PDF. Either a scan of a paper form, or a designed form exported from Word / InDesign without interactive fields. One file at a time.
2. Run auto-detect (optional). Click "Auto-detect fields" — the tool scans every page for underline blanks, boxed blanks, and checkbox squares and creates a fillable field at each detected location. Auto-detect handles most clean form layouts; review the proposed fields before accepting.
3. Add fields manually where auto-detect missed. Pick a field type from the toolbar (text, checkbox, radio, dropdown, date), then click-and-drag a rectangle on the page where the field should go. Adjust position and size by dragging the field handles afterwards.
4. Configure each field. Click a field to open its property panel: name (used in form-data export), label, placeholder text, font and size, required / optional, and type-specific options (max length for text, options list for dropdown, regex pattern for validation).
5. Build radio groups for mutually exclusive options. Add the first radio field, name the group (e.g. "marital_status"), then add the remaining options with the same group name and different export values ("single", "married", "other"). The PDF reader will enforce one-of-N selection at fill time.
6. Preview by filling. Toggle "Preview mode" and try filling each field as the recipient would. Watch for fields whose tab order skips around the page in unexpected ways — set explicit tab order in the Advanced section if the auto-ordering is wrong.
7. Click Download. The tool writes a new PDF with the AcroForm dictionary populated, every field added as a page annotation linked to the AcroForm entry, and field-rendering appearance streams generated so the field looks right in readers that do not auto-render appearances. Output downloads automatically.
8. Test in the readers your recipients will use. Acrobat Reader, Preview (macOS), the built-in viewer in Chrome / Edge / Firefox, and iOS Files cover >95% of real-world recipients. Open the output in each, fill a field, save, reopen, confirm the value persists.

How ScoutMyTool compares to Smallpdf, iLovePDF and PDF2Go

All four offer some flavour of fillable-PDF creation, but the free-tier limits differ sharply.

AcroForms vs XFA — and why you want AcroForms

PDF has two different form mechanisms. AcroForms is the original, defined in PDF 1.2 (1996) and standardised in ISO 32000-1 §12.7¹. XFA (XML Forms Architecture) was added in PDF 1.5 (2003), based on an Adobe proprietary XML schema, and deprecated by the ISO PDF committee for PDF 2.0 in 2017². The practical difference for form-makers:

• AcroForms fill in every modern reader.Acrobat, Foxit, Preview, every browser's built-in viewer — they all read the /AcroForm dictionary and present interactive fields.
• XFA forms fill only in Acrobat. Other readers display either the static rendering or an "open this in Acrobat to fill" prompt. The user experience for non-Acrobat recipients is bad.
• The IRS, SSA, and other US federal agencies have moved away from XFA for downloadable forms specifically because of XFA's reader-compatibility problems³.

ScoutMyTool generates AcroForms. The output works everywhere the PDF specification works, and it will keep working when XFA support is removed from future Acrobat releases (Adobe has announced the eventual removal but not committed to a date).

Related PDF tools on ScoutMyTool

• Fillable PDF — the tool this guide is about.
• PDF Form Filler — fill a fillable form yourself (the recipient side of the workflow).
• Flatten PDF — lock the filled fields into static page content before sending the final copy.
• eSign PDF — add a signature to the filled form.
• PDF Editor — for more granular field placement and styling.
• Fill W9 online free — task-specific example: making the IRS W-9 fillable.
• Unlock PDF — required first if the source is password-protected.

Frequently asked questions

I have a paper form scanned to PDF. Can I turn it into a fillable form?

Yes. Upload the scanned PDF, click "Auto-detect fields" — the tool runs a layout heuristic that detects underline-style blanks, boxed blanks, and checkbox squares, and creates a fillable field at each detected location. The auto-detect is good but not perfect on hand-drawn forms; review the detected fields and manually add / remove any the heuristic missed or mis-placed. The result is an interactive PDF whose fields the recipient can fill in any reader — Acrobat, Preview, Edge, Chrome built-in viewer.

What field types can I add?

Five core types, covering 95% of real-world forms: (1) text input — single-line or multi-line, with optional max length and input mask; (2) checkbox — independent on/off; (3) radio group — exactly one of N options selected; (4) dropdown — picklist with predefined options; (5) date — calendar picker (rendered as a styled text input in readers that do not support date pickers natively). Less common: signature fields and image upload fields are available in the Advanced section.

Can I add validation rules — required fields, number ranges, regex patterns?

Yes, with caveats. Each field has a "required" toggle that surfaces in the reader's "Submit" or "Save" path. Numeric fields accept a min / max range. Text fields accept a regex pattern for format validation (e.g. ^[0-9]{5}$ for a US ZIP). Validation runs in the reader, not in ScoutMyTool — so it depends on the reader respecting the JavaScript actions defined in the PDF's /AcroForm dictionary. Acrobat and Foxit honour all the validations; Preview and browser-built-in readers honour required and some basic ranges but skip the more sophisticated regex paths.

How do I make checkboxes that are mutually exclusive (radio buttons)?

Use the "Radio group" field type, not the checkbox type. Mark the first option as the group anchor, then click each subsequent option while holding the "Add to group" toggle. All members of a radio group share the same internal field name with different export values; the PDF reader enforces "only one selected at a time" for any field with that name. Mechanically the field type is /Btn with the Radio flag set per ISO 32000-1 §12.7.4.2 — the same mechanism Acrobat uses internally.

Is my PDF uploaded to your servers?

No. The field-creation operation runs entirely in your browser using pdf-lib. Your file is loaded into a sandboxed memory buffer, fields are added to the /AcroForm dictionary and page annotations, and the modified file is delivered as a download. Verify in DevTools Network — zero outbound requests. Important for sensitive forms (HR onboarding packs, medical intake, financial disclosures) that should not be uploaded before they have even been filled out.

Will the form work in mobile PDF readers?

In most of them, yes. iOS Files / Books, Adobe Acrobat Reader, Foxit, and the Google Drive PDF preview all support filling AcroForm fields. The Apple Mail preview pane does NOT support filling — recipients on iPhone must open the attachment in Files or Acrobat. If your recipients are likely to try filling in Mail directly, add a one-line note: "Tap the attachment to open it in Files before filling".

Can recipients save the filled form, or only print it?

Save the filled form, on any reader that supports AcroForms. The fields are first-class PDF objects, and the reader can save the values back into the file. Some legacy free readers (notably some older Adobe Reader versions on Windows) save-disable when the form does not have "Extended Reader Rights" — a paid Adobe-server feature. ScoutMyTool does not stamp Reader Rights (it requires a paid Adobe service), but every modern free reader saves fine without them, including all of Acrobat Reader from 2017 onwards.