How to Fill Out a PDF Form on an iPhone

Some forms have interactive fields built in. Others are flat, with no tappable fields at all. And Apple includes a basic built-in option that works offline.

This guide covers all three:

• Fillable PDFs with interactive fields

• Flat or scanned PDFs where you add text on top

• Apple Preview for a built-in, offline option

Best of all, the steps work on iPad, too.

Interactive PDFs have clickable text boxes, checkboxes, and dropdowns built into the file. These are the straightforward ones. A browser-based PDF Form Filler reads those fields correctly and lets you fill them out without downloading anything.

1. Open the PDF Form Filler

• Go to our PDF Form Filler in your favorite browser on your  iPhone.

• Tap “Choose Files” to upload your PDF.

• You can pull it from the Files app, your camera roll, Google Drive, OneDrive, or Dropbox.

No sign-up needed to start.

Start here: Use the form filler below to upload your PDF and start filling it on your iPhone.

2. Tap Each Field and Type Your Answer

• Tap any interactive field. Your iPhone keyboard will open automatically.

• Fill in your answer and move to the next field.

• Checkboxes toggle on and off with a single tap.

• Dropdowns work the same way.

• Scroll through each page and fill as you go.

3. Review the Form, Then Download

• Scroll through the completed form to check every field.

• Tap “Download” or “Finish” when you're done.

The filled PDF saves to your iPhone in its original format, with layout, fonts, and spacing intact.

If you regularly fill out PDF forms on your iPhone, you can also use the Smallpdf iOS app instead of working in a browser. It gives you access to the same PDF tools in a dedicated app, so you can upload, fill, sign, and export documents directly from your device.

Flat PDFs have no clickable fields underneath. They're common with scanned documents, older government forms, and templates printed to PDF. To fill out this kind of PDF on an iPhone, you add text on top of the page.

1. Upload Your Flat PDF

• Open our PDF Form Filler on your iPhone.

• Upload your flat PDF.

The tool switches to free-form editing mode automatically.

2. Place a Text Box Over Each Field

• Tap “Add text” button.

• Drag your finger over the field you want to fill.

• Type your answer.

• Adjust the font size so the text fits neatly inside the field.

• Repeat for each field, working top to bottom.

3. Add a Signature if the Form Needs One

Lease agreements, consent forms, and onboarding documents usually need a signature too.

• Tap the “Signatures & initials” tool to draw with your finger, type your name, or upload an image.

• Position it over the signature line.

4. Download the Completed Form

• Tap “Download” or “Finish” when you're done.

The file saves as a standalone PDF on your iPhone, ready to email, upload, or share from the Files app.

Preview is built into iOS 26 and iPadOS 26. PDFs open in it automatically, so there’s no extra app required. It works offline, which makes it useful when you don’t have a connection.

It’s best for adding text or a signature. For long, multi-field forms, a dedicated form filler is usually faster.

1. Open the PDF in Files or from Mail

• Open the Files app and locate your PDF or tap it directly from an email attachment.

• The document opens in Preview automatically.

2. Open the Annotation and Form Tools

• Tap the pen icon at the bottom left of the screen.

• A row of annotation tools appears. Tap the “+” button to open additional options, including “Add Text” and “Signature.”

3. Add Text to Each Form Field

• Tap “Add Text.” A text box appears on the page.

• Drag it over the field you want to complete.

• Tap inside the box to type your answer.

• Adjust size or position so it fits neatly within the form.

• Repeat for each field.

• To add a signature, tap “+” and choose “Add Signature,” then position it over the signature line.

4. Save or Share the Completed PDF

• Preview saves changes automatically.

• If you need to keep the original file untouched, create a duplicate before editing.

When you’re done, tap the share icon at the bottom right to send or export the completed PDF. Or tap the back arrow at the top left to return to the previous app.

If tapping a field does nothing, one of these is usually the reason.

• The PDF is flat or scanned. A scanned form, a document printed to PDF, or a Word file saved straight to PDF won't have interactive fields. You will need to add text manually. Follow the steps above for filling out a non-interactive PDF on an iPhone.

• The form is password-protected. Some PDFs require a password before you can edit or fill them out. If you have the password, you can unlock the file first using the Unlock PDF tool.

• The fields are set to read-only. If the person who created the document locked the fields or restricted editing permissions, they won’t be fillable. You may still be able to manually add text over the form instead, or ask the document creator to remove the restrictions and resend the file.

If you regularly work with flat, non-interactive PDF forms, adding PDF Form Filler to your workflow will give you the most control on an iPhone—and iPad—without downloading anything.

Smallpdf’s PDF Form Filler is free to use with basic daily limits, which is usually enough for occasional forms. If you’re filling out multiple documents, working with larger files, or need full access to all editing tools, Smallpdf Pro removes those limits. You can try Pro free for 7 days to see if it fits your workflow before committing. The same tools are also available in the Smallpdf iOS app.