How to fill out a PDF form
First check whether the form has fields. That tells you whether to fill a control or place text over the page.
Free toolPDF Form FillerFill PDF fields or place answers on flat pages. Review required fields, undo edits and save an editable or flattened copy.Fill a PDF formThe short answer
Open the PDF and click a blank answer box. If you get a cursor or a checkbox, fill its existing fields. If nothing happens, use an add-text tool to place answers over the page. Save a new copy and reopen it before sending.
- Read the form’s instructions and any required date format.
- Enter answers in existing fields where possible.
- Add text or marks to flat areas only when the recipient accepts that format.
- Save an editable copy. Flatten a separate copy if needed.
- Reopen the saved result and check every page.
Why some PDFs will not let you type
A PDF can look like a form without containing any form controls. A scan is usually a picture of a printed page. Its lines are pixels, not inputs.
| What you have | How to fill it | What to watch |
|---|---|---|
| Standard interactive form | Type into its text fields. Use its checkboxes and lists. | Long answers can exceed a field’s visible area. |
| Flat PDF or scan | Place text and marks over the page. | These additions do not create interactive form fields. |
| XFA or scripted form | Use the application recommended by its issuer. | Browser tools may not support calculations or dynamic sections. |
| Certificate-signed PDF | Ask for the correct unsigned copy or use an authorised signing workflow. | Editing can invalidate an existing signature. |
Choose a method for your device
A focused browser editor suits ordinary forms. A desktop reader is a better choice when the document depends on specialised PDF behaviour.
Fill a PDF in your browser
In floi, the page stays beside a list of answer fields. Open the PDF, type your answers and use Next required to review blanks. On a flat page, choose Text or a mark and tap its position.
The PDF and answers stay in this tab. They do not become account drafts. Keep the tab open until you save your work.
Use Adobe Acrobat Reader
Reader is a useful starting point when a form’s issuer recommends Adobe. Its Fill & Sign tools cover interactive fields and placed text. Check the issuer’s instructions for XFA, calculations and certificate signing.
Adobe explains its workflow in the Reader form-filling documentation. Its online filler separately asks you to sign in, as described on Adobe’s PDF filler page.
Use Preview on a Mac
Preview can fill supported interactive fields and add text when a page has none. Save a duplicate before editing, then check the completed copy. Apple documents these controls in Fill out and sign PDF forms in Preview.
Fill a PDF on a phone
Use a readable field panel when the original boxes are too small to tap. For placed text, zoom in and check the whole line after adding your answer. Keep a local copy before switching apps or closing the tab.
Editable and flattened copies solve different problems
An editable copy keeps the form’s controls. A flattened copy paints the answers into the page and removes those controls.
| Choose | When it helps | Limit |
|---|---|---|
| Editable | You or the recipient may need to revise an answer. | PDF readers can display field appearances differently. |
| Flattened | The recipient wants an ordinary completed page without interactive controls. | It is still editable in a PDF editor. Flattening is not security. |
| Printed and scanned | The recipient specifically requires handwriting or a paper process. | Searchable text and document accessibility can be lost. |
A worked example: one form, two kinds of page
The floi sample uses six interactive fields on its first page. Its second page has a date line and a drawn checkbox. You can reproduce the difference with Try a sample form.
Fill the interactive page
Enter a name and email. Pick a session and experience. Notes and updates are optional, so you can leave them blank.
Complete the flat page
Move to page two. Choose Date and place it above the line. Use Tick for the printed checkbox.
Keep both copies
Save with editable fields, then choose Flatten form fields and save again. Reopen each copy and try changing the name.
This is a reproducible functional example, created on 20 October 2026. It demonstrates the two input types. It is not a speed benchmark or a claim about every PDF reader.
Check what matters before returning the form
Reopen the actual saved file, rather than relying on the editor preview. A PDF stores field data and visible appearances separately.
- Read long names and addresses at the right edge of each box.
- Check radio choices, ticks and dates.
- Look at every page, including instructions and attachments.
- Use the date format requested by the issuer.
- Confirm that any signature method is accepted by the recipient.
- Keep the original and an editable working copy.
What the browser approach gives up
floi does not run PDF JavaScript, calculate totals or create form templates. Acrobat and specialist desktop tools have a broader PDF feature set. Use those when the form needs them.
The benefit here is a focused local workflow with a page preview, required-field review and reversible edits. Files are limited by browser memory, so large documents may need a desktop app even below the stated 100 MB limit.