Skip to main content

Fill PDF Form Online Free — PrivaTools

TL;DR: Upload a fillable PDF form, set values for each field, and download the completed copy. No Acrobat required.

Fill PDF forms online for free — open interactive PDF forms, fill in all text fields, checkboxes, and dropdowns, then save the completed document. No Adobe Acrobat needed.

Fill PDF Form is one of 179+ free file utilities on PrivaTools. The entire stack is open source under the MIT license, so the privacy guarantees can be audited end-to-end. You can also run all 179 tools on your own infrastructure with one docker compose command.

How to Fill PDF Form with PrivaTools

  1. Upload a fillable PDF form — Drop a PDF with AcroForm fields up to 500 MB. The tool detects form fields automatically.
  2. Fill in the values — Provide a JSON object mapping field names to values: text strings for text fields, true/false for checkboxes, option labels for radio buttons / dropdowns.
  3. Download the filled form — Click Fill. The PDF is returned with values populated. Field structure is preserved so the form can be filled again later.

Frequently Asked Questions

How do I know what the form field names are?

Use the /api/fill-form/fields endpoint (or paste-then-inspect): PrivaTools returns the list of field names, types, and current values without filling anything.

Can I flatten the filled form?

Yes — run the Flatten tool afterwards to bake the values into the page content so they can't be edited.

Does this work on signed forms?

Filling a signed form invalidates the signature. Sign last, after filling.

Last reviewed 2026-05-01 by the PrivaTools maintainers. Source code on (MIT-licensed, self-hostable).

Related PDF Tools

Mentioned in our guides

See how PrivaTools compares to iLovePDF, Smallpdf, Adobe Acrobat, and other free PDF tools.