Fill PDF

What is Fill PDF?

Fill PDF lets you complete a PDF form and save the filled copy. If the document has interactive fields, the tool detects them and lets you type into text boxes, tick checkboxes, and choose from dropdowns, then writes your answers back into the file. If the PDF is flat, with form lines printed as part of the page rather than as real fields, you can still place your own text wherever it is needed and export a finished document. Filling is handled in your browser with pdf-lib, so your form never leaves your device. This matters for the personal data forms usually contain, such as names, addresses, and ID numbers. The output is a standard PDF that preserves the original layout, fonts, and any fields you did not touch, so the document looks exactly as the issuer intended with your entries in place.

Why use this tool?

Form filling runs entirely in your browser, so the personal and financial details you enter never get uploaded or stored on a server. Interactive fields are written back natively, and any fields you leave alone are preserved exactly, along with the document's layout and fonts. Flat PDFs are supported through added text rather than altered content. There are no watermarks, sign-ups, or page limits, and the tool works offline once loaded, making it a private, reliable way to complete and download a finished form in one place.

Common use cases

Use this to complete application forms, tax documents, registration sheets, consent forms, and contracts that arrive as PDFs. It is ideal when you would rather type clean entries than print, hand-write, and rescan a document. The interactive-field mode suits properly built government and corporate forms, while the free-text mode handles flat or scanned forms that lack real fields. It is also handy for adding a quick note, reference number, or date to a PDF without opening a full editor. Because everything stays local, it is well suited to forms containing sensitive personal or financial information you do not want to upload.

How to use Fill PDF

1. 1Open the Fill PDF tool and load your form.
2. 2Let the tool detect interactive fields, or switch to free-text mode for flat PDFs.
3. 3Type into text fields, tick checkboxes, and select dropdown options as needed.
4. 4For flat forms, click where you want text and type your entry.
5. 5Download the completed PDF.

Frequently asked questions

Is my form data uploaded?

No. All filling happens in your browser with pdf-lib, and the form plus everything you type stays on your device. Nothing is sent to a server or stored, which is important because forms usually contain sensitive details like names, addresses, and ID numbers. Once the page loads you can fill forms offline.

What if my PDF has no interactive fields?

Switch to free-text mode, which lets you click anywhere on the page and type. This is for flat or scanned forms where the lines are part of the page image rather than real fields. Your text is placed as a new layer on top, so the original document underneath is left unchanged.

Are my unfilled fields and the rest of the document preserved?

Yes. Fields you do not touch keep their existing values or stay empty, and the rest of the document, including layout, fonts, images, and page count, is preserved. The tool writes only the entries you make, so the finished form matches the original design with your answers added.

Can I edit my entries after saving?

Interactive fields you fill remain editable in PDF viewers that support forms, so you or a recipient can adjust them later. Free-text additions on flat PDFs are placed text and are best changed by re-running the original through the tool. Your source file is never overwritten, so you can always start fresh.

Does it work on mobile?

Yes. You can fill both interactive and flat forms in a modern mobile browser on iOS or Android. Tapping a field brings up your keyboard, and dropdowns and checkboxes respond to touch. The completed PDF downloads to your device, with all processing done locally rather than on a server.

Will the form still be accepted after I fill it digitally?

Filled interactive forms remain valid PDFs that issuers accept the same as any typed submission. For flat forms, your placed text appears clearly on the printed or shared copy. If a form requires a handwritten or certified digital signature, complete the fields here and apply the required signature separately as the issuer instructs.

1. 1Try interactive-field mode first; only switch to free-text if the form has no real fields.
2. 2Tab between detected fields to move quickly through long forms.
3. 3Match your free-text font size to the surrounding form so entries look consistent.
4. 4Keep a blank copy of the original so you can fill the same form again later.

How does it compare?

Adobe Acrobat offers the most complete form tooling, including field creation and certified signatures, but requires its app and often a subscription. Smallpdf and iLovePDF can fill forms but typically upload your file to their servers and gate features behind accounts. This tool fills both interactive and flat PDFs entirely in your browser, keeping sensitive entries private and free of watermarks. For pure field creation or certified e-signatures, a full suite is still better; for filling and saving privately, this is faster.

Related tools

More free tools. No signup, no watermarks.