Flatten a PDF

An interactive PDF has layers that sit on top of the page: form fields you can type into, comments, highlights, stamps, drawn shapes and signatures added as annotations. Different PDF readers display these layers differently, and anyone can change them.

Flattening merges those layers into the page itself. After flattening, the filled-in answers, stamps and markup look the same in every reader and printer, and they can no longer be edited as fields or annotations.

Use Flatten form fields for completed forms: tax forms, applications, contracts with filled fields. The values become ordinary page content, so they display correctly everywhere, and the text stays crisp and searchable.

Use Flatten everything when the PDF has annotations that must be preserved exactly as seen, such as review comments, approval stamps or drawn markups, or when you want a file that is as close to a printed paper copy as possible. If you need searchable text afterward, run OCR PDF.

• Before sending a completed form, so the recipient sees exactly what you filled in and can't change it accidentally.
• When fields appear empty in someone else's reader or on a phone. Flattened values always show.
• Before printing or archiving, so the record does not depend on interactive features.
• Before merging with other documents; some tools drop form fields or mix up fields with the same name across files.
• After signing a visual signature, so the signed version is locked in.

Keep an unflattened copy if you might need to change the answers later; flattening cannot be undone.

Flattening happens in your browser, so filled-in forms with personal details are never uploaded. If the PDF has no fillable fields and you chose Flatten form fields, the tool tells you and suggests Flatten everything instead.

Your original file is not changed; the flattened copy downloads as a new file with -flattened added to its name.

You filled out a fillable job application and want to email it so the employer sees exactly your answers. Open the filled PDF here, choose Flatten form fields, and click Flatten PDF. The tool reports, for example, Flattened 42 form fields. The answers are now part of the pages, the text is still searchable, and the employer's software cannot show blank fields or let anyone edit your answers.

Flattening is one of several ways to make a PDF harder to change, and they work well together:

• Flatten removes the editable layers, so answers and markup become fixed page content.
• Password protect PDF can restrict editing and copying in readers that honor permissions, and an open password keeps the file private.
• A certificate-based digital signature (applied with dedicated signing software) shows whether the file was changed after signing; check one with Verify PDF signature.

None of these makes a PDF impossible to edit for someone with editing software, but flattening removes the easy, accidental and casual changes.