Form Filler
Detect and fill PDF form fields in your browser. Nothing uploaded.
Select a PDF form
or drop one PDF here
That PDF does not have AcroForm fields. If it has visible boxes you can type into in Adobe Reader, it might be an XFA form (legacy / corporate template) which this tool does not support.
Your file is ready
Processed entirely in your browser — the file never left your device.
How to fill a PDF form
Three steps. All in your browser.
Pick the PDF
Drop or select the form. It is read locally.
Fill the fields
Inputs are generated automatically from the form definition.
Apply & download
The filled PDF is saved locally. Tick Flatten to lock the values.
What is a "PDF form filler"?
A PDF form filler is a tool that detects the interactive fields baked into a PDF — text boxes, checkboxes, radio groups, dropdowns — and lets you type values into them, save the file, and pass it on. Most real-world PDFs that look like forms are AcroForm-based: IRS 1040s, school applications, banking onboarding packets, and anything a Word file with form controls gets exported to.
The output is a normal PDF that any reader can open. If you tick Flatten before downloading, the values become part of the page and the recipient cannot edit them anymore — useful when sending a completed form for signature or filing.
How form filler works in your browser
When you drop a PDF, the tool parses the AcroForm with pdf-lib and reads the type and options of each field. A matching HTML input is generated for every field — a text box for text fields, a checkbox for checkboxes, a radio group with the producer's options, a select for dropdowns, and a multi-select for option lists. You fill in the values exactly as you would in Adobe Reader.
When you click Apply, the tool writes each value back into the PDF, regenerates the field appearance streams so the values are visible everywhere, and saves the result locally. There is no upload, no temporary server-side file, and no third party in the loop.
Common use cases
- Submitting tax or government forms. Fill an official PDF without printing it, then export the flattened result for filing.
- Onboarding documents. Fill a HR PDF with your details locally; flatten before emailing back so the values stay put.
- Banking applications. Most onboarding PDFs are AcroForms — fill them in the browser and avoid the desktop-Adobe round-trip.
- Routine paperwork. School consent forms, gym waivers, leasing addenda — anywhere a PDF wants typed input.
- Bulk pre-fill. Generate one PDF per recipient by scripting against the same core function used by this page.
Privacy & security
Filling a form often means entering personally identifiable data — names, addresses, ID numbers, sometimes financial details. Most online PDF fillers upload the PDF and the values to their servers and trust their retention promises. imisspdf does the entire operation inside your tab with pdf-lib. The form definition, your inputs, and the filled PDF all stay in your browser memory and disappear when you close the tab.
Frequently asked questions
Any PDF that contains a standard AcroForm — the form type used by IRS forms, government applications, banking PDFs, and anything created by Word's "Save as PDF" with form controls. XFA forms (mostly older corporate templates) are not supported because they are essentially XML applications, not a feature of the PDF spec.
Yes. The tool reads the form definition, builds inputs in your browser, and applies your values locally with pdf-lib. Nothing is uploaded. When you click Download, the filled PDF is offered straight from your tab; close the tab and every value is gone.
Flatten bakes the values you typed into the page content so they look the same but cannot be edited anymore. Useful when sending a completed form to someone who should not be able to change it. If you leave flatten off, the recipient can still open the PDF in Adobe Reader and edit the fields.
The form author marked them that way. Computed totals, signature blocks, and pre-filled disclaimers are commonly read-only. The tool will show them but will not let you change them, which keeps the document valid for the entity that designed it.
Some PDFs reach the filler without "appearance streams" generated for their fields. The tool runs updateFieldAppearances() before saving, which fixes most cases. If you still see blanks, tick the Flatten box on Apply — flattening renders the value into the page directly, so it always shows.
Tips for best results
- Flatten before emailing back. It guarantees the recipient sees the values you entered, in case their reader does not regenerate appearances.
- If a field is read-only, leave it alone. The author marked it that way on purpose — usually because the value is calculated.
- For XFA forms, save as flat PDF first. Open the file in Adobe Reader, print to PDF, then re-import here. The result is a normal AcroForm or a flat page you can annotate instead.
- Combine with Sign PDF. Fill the form, sign it, then flatten — same workflow Adobe Sign uses, only in your browser.
Related PDF tools
- Flatten PDF — flatten an already-filled form so it cannot be edited.
- Sign PDF — add a signature to a filled form.
- Merge PDF — bundle a filled form with its supporting documents.
- Unlock PDF — remove a password before filling.