How do I know if a PDF is fillable?

If clicking a blank in the form places a text cursor and lets you type, it has interactive fields. If nothing happens, it's a flat (non-fillable) form.

Can I fill a form that isn't fillable?

Yes — use Edit PDF to add your own text boxes on top of the page, or print it and complete it by hand.

How do I stop someone from changing my entries?

Flatten the form before sending it. Flattening bakes the values into the page so the fields can no longer be edited.

Is my form data uploaded?

No. Filling and flattening run in your browser, so your personal details stay on your device.

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What is a fillable PDF form?

Last updated: October 7, 20262 min readEdit PDF

A fillable PDF form has interactive fields — text boxes, checkboxes, and dropdowns — that you complete on screen instead of printing and writing by hand. To fill one, open the Fill Forms tool, type into the fields, and download your completed copy; flatten it to lock the answers. It all runs in your browser.

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Quick steps

1Open Fill Forms and add the fillable PDF.
2Type into each field (text, checkboxes, dropdowns).
3Download the completed copy; flatten it to lock the answers.

What makes a form “fillable”

A fillable PDF contains interactive form fields (an AcroForm) layered over the page — named boxes that accept typed text, checkmarks, or a choice from a list. A plain PDF of a form has none of these; it's just an image of a form.

How to fill one

Open Fill Forms, add the PDF, and type into each field. Your entries stay sharp and readable, and you download a completed copy — no printing, scanning, or handwriting.

Locking your answers

Form values stay editable by default. To stop anyone from changing them, flatten the form with Flatten PDF before sending — this bakes your answers into the page.

What if the form isn't fillable?

If a PDF has no interactive fields, you can't click into it. Use Edit PDF to place your own text on the page, or print it and fill it by hand.

Tools mentioned in this guide

Frequently asked

How do I know if a PDF is fillable?: If clicking a blank in the form places a text cursor and lets you type, it has interactive fields. If nothing happens, it's a flat (non-fillable) form.
Can I fill a form that isn't fillable?: Yes — use Edit PDF to add your own text boxes on top of the page, or print it and complete it by hand.
How do I stop someone from changing my entries?: Flatten the form before sending it. Flattening bakes the values into the page so the fields can no longer be edited.
Is my form data uploaded?: No. Filling and flattening run in your browser, so your personal details stay on your device.

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