Fill PDF Form Online
Fill out interactive PDF forms in your browser. AcroForms supported, files stay on your device. Free, no signup, no watermark.
Why fill PDF forms with PDFWix?
- AcroForms detected automatically: Drop your document in; every fillable field is listed and the right input type per field — text, checkbox, radio, dropdown, multi-select — is picked automatically. No manual mapping.
- Honest about XFA: If the PDF is XFA (Adobe LiveCycle), we say so clearly and point you to Adobe Reader. Most modern govt forms are AcroForms — XFA is a shrinking minority. Better to know than to silently get a broken file.
- Optional flatten: Toggle on to bake values permanently into the page (for final submission), or off to keep editing later. Most other tools either always flatten or never do.
- Files stay on your device: The whole pipeline runs in your browser via pdf-lib. Tax forms, SSNs, salary numbers, signatures — none of it ever reaches our servers.
- Read-only fields respected: Fields the form's author marked as read-only (e.g. calculated totals on tax forms) are shown but disabled — we don't pretend to write where the form forbids it.
- Free, no signup, no watermark: Fill as many forms as you need without a paywall. The output PDF has no PDFWix branding.
Common ways people use this tool
- Filling a current IRS W-9 to send to a new client
- Completing a 1040 draft before printing for tax-prep meeting
- Onboarding paperwork from a new employer (I-9 page 1, W-4, direct deposit forms)
- Apartment rental applications and lease addendums
- Insurance claim forms and HSA reimbursement requests
- School permission slips and after-school enrollment forms
How to fill a PDF form
- Drop in your fillable PDF — Click "Select PDF form" or drag a PDF with form fields into the upload box. We read it instantly in your browser — nothing is uploaded.
- Review the detected fields — We auto-detect every AcroForm field — text, checkboxes, radio groups, dropdowns, multi-select lists — and render the matching input for each one. Field labels come from the form's internal field names.
- Type or pick your answers — Fill in only the fields you need. Read-only fields (like calculated totals) are shown but disabled. Signature fields are skipped here — use Sign PDF after you finish filling.
- Flatten if you're done editing — Toggle "Flatten before download" on for a final submission copy — the values become part of the page and can't be re-edited. Leave it off if you want to keep filling later.
- Download the filled PDF — The result is named yourfile-filled.pdf. Reopen in Adobe Reader, Preview, or any browser to confirm the values are in place.
Tips for filling PDF forms
- Check for a fillable-fields indicator first — Some PDFs look like forms but are just flat scans with printed lines. If PDFWix reports no fields, the document isn't a real AcroForm — use [Edit PDF](/edit-pdf) instead.
- Flatten before you email a final copy — Leaving a form unflattened means the recipient's PDF viewer might let them edit your answers. Toggle "Flatten before download" on for anything you're submitting as final.
- Save an unflattened copy for yourself — Keep one unflattened version before you flatten and send — if you need to correct a typo later, you'll need the editable original.
- Read-only fields aren't a bug — Greyed-out boxes are usually auto-calculated totals the form's author locked. That's expected behavior, not something to work around.
- Combine with Sign PDF for signature fields — Fill PDF Form skips signature fields on purpose — finish typing everything else first, then run the result through [Sign PDF](/sign-pdf) to add your signature as a separate step.
How PDFWix form filling compares
| Feature | PDFWix | iLovePDF | Smallpdf | Adobe Acrobat Online |
|---|
| Free, no daily limit | ✓ Always | ✗ 2 tasks/day | ✗ 2 tasks/day | ✗ Limited free |
| No signup required | ✓ Never | ✗ Required | ✗ Required | ✗ Required |
| Files stay in browser | ✓ WebAssembly | ✗ Server upload | ✗ Server upload | ✗ Server upload |
| Auto-detects form fields | ✓ | ✓ | ✓ | ✓ |
| Fills text, checkbox, radio, dropdown | ✓ | ✓ | ✓ | ✓ |
| No watermark on output | ✓ | ✓ | ✓ | ✓ |
Comparison based on publicly documented free tier limits as of July 2026.
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Frequently asked questions
I dropped my PDF and got 'No fillable fields found.' What now?
Your PDF doesn't have AcroForm fields baked in — visually the boxes are just lines on the page. Use Edit PDF to add text overlays anywhere on a non-fillable PDF, or Sign PDF if you only need to add a signature.
Does PDFWix support government forms?
Most modern IRS forms (1040, W-9, W-2 series), and the majority of HR and federal application forms, are AcroForms — those work here. Some older USCIS forms and a handful of state DMV forms are XFA (Adobe LiveCycle). We detect XFA and clearly tell you to use Adobe Reader instead.
Can I save the form without flattening so I can keep editing later?
Yes — toggle "Flatten before download" off. The downloaded PDF keeps its form fields intact — reopen it in PDFWix, Adobe Reader, or any other AcroForm-aware viewer to continue filling.
Is filling private? Where does my data go?
Filling runs entirely in your browser using pdf-lib (a JavaScript PDF library). Your form, your typed values, and the resulting filled PDF never reach our servers. Close the tab and there's no record anywhere.
Why are some checkboxes greyed out and not editable?
Those fields are marked read-only by the form's author — usually because they're auto-calculated (e.g. a total on a tax form) or are intended to be filled by another party. Adobe Reader behaves the same way; we don't pretend to write where the form forbids it.
How do I fill out a form online for free?
Open PDFWix Fill PDF Form, drop in your document, and every fillable field is detected automatically — text boxes, checkboxes, radio buttons, and dropdowns. Type your answers directly in the browser, then download the completed file. No signup, no cost, and nothing is uploaded to a server at any point.
Can I fill out a form on my phone?
Yes. Open pdfwix.com/fill-pdf-form in Safari on iPhone or Chrome on Android — the field detection and typing experience work the same as on desktop. For touchscreens, PDF Studio (linked above) gives a larger tap-friendly layout for filling fields directly on the page.
What happens if my PDF has no fillable fields at all?
You'll see "No fillable fields found" — this means the PDF's boxes are just visual lines, not real interactive AcroForm fields. Use Edit PDF instead to type text anywhere on the page as an overlay, which works on any PDF regardless of whether it has form fields.
Need to add a signature too? After filling, run the result through Sign PDF. For non-fillable PDFs (no AcroForm fields), use Edit PDF to add text overlays anywhere. To lock the filled form before emailing, use Protect PDF.