What's the difference between /T and /TU?

/T is the field's internal identifier (used in form processing). /TU is the user-facing tooltip. Screen readers announce /TU; sighted users see it on hover. /T is functionally invisible.

Does this affect form-fill behaviour?

No — the field's data and validation rules are unchanged. Only the tooltip is added.

Are the files uploaded?

No — pdf-lib applies the changes locally.

Form Label Association

Apply /TU tooltips to AcroForm fields — the screen-reader label for every form input.

Your files never leave your browser. All processing happens on your device — nothing is uploaded.

1. Upload your file

Drop a PDF file here

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How does the Form Label Association work?

Set the screen-reader tooltip (the /TU entry) on every AcroForm field in your PDF. Without /TU, screen readers fall back to the field's internal name — usually a useless string like "Text1" or "patient_name_v2_fixed". With /TU set, they announce a friendly description like "Patient full legal name" — a major accessibility improvement that takes thirty seconds. Use Extract Form Data to CSV first to discover your form's exact field names, then map each one to a tooltip in the textarea below.

🔒 Security & Privacy

All processing happens on your device. Your files never leave your browser, never touch our servers, and are not stored anywhere. Close the tab and the file is gone.

📱 Use it on any device

Works in any modern browser — Mac, Windows, Linux, iPhone, Android, and tablets. No installation, no app to download. Just open the page and start.

⚡ Quick & easy

Drag, drop, click. Most files process in seconds, not minutes. No watermarks added to your output, no per-day limits, and the tool always shows the result before asking you to download.

🎁 Always free, no signup

Free to use, every time. No account creation, no email required, no “trial” that converts to a paid plan. We make money from ads so you don’t have to pay.

Frequently asked

Run Extract Form Data to CSV on a copy of your form. The header row of the resulting CSV lists every field name. Use those names exactly in your "name=tooltip" lines.