Flatten a filled PDF form so the answers stay put

Flatten your filled form now

Drop the filled PDF, or several. Each comes back as a new file with -flat at the end of its name, and the original stays as it was.

What does flattening a form actually do?

A filled form is 2 layers: the printed page, and a layer of fields on top that a viewer draws and lets you change. Flattening draws that layer into the page the way it looks now, then takes the fields and the form out of the file.

We filled an invented rental application (9 fields on page 1: a name, a several-line “About you” box, a read-only reference number, a checkbox, 3 radio buttons, a dropdown and a list, plus an empty signature field on page 2) with “Jane Cooper”, Graz and the rest, then flattened it:

2 of those rows surprise people. The answers become ordinary page text, so they are easier to copy out after flattening, not harder. And the file got smaller here because the form’s machinery left with the fields; on a form that is mostly scanned pages, expect almost no change in size.

How do I flatten a form I am filling in getPDF?

1. Fill the form in the form filler: click a tinted field, type, Tab to the next one.
2. Sign it, if it needs a signature. Click the “Sign here” field or use the Sign tool. Do this before flattening: an empty signature field turns into empty page.
3. Save the fillable copy first. Click Save. This copy, ending in -edited, keeps every field, so you can correct an answer next week.
4. Then open the menu next to Save (More ways to save; on a phone, More) and pick Save flattened PDF. Its note says it plainly: “Filled fields and marks become part of the page, so nobody can change them. A note keeps only its icon.” The flat copy ends in -flattened.
5. Send the flattened copy. Keep the -edited one.

The editor’s flattened save runs exactly the same step as the Flatten PDF tool above, so the result is the same either way.

How do I check it worked?

• Open the flat copy in the editor. With the Select tool there is no “This file is a form” hint in the options bar and no blue field tint on the page.
• Or drop it on Inspect. It says “Form: no form”.
• Or open it in any viewer and click an answer. Nothing opens. In Chrome or Acrobat Reader, a flat form looks exactly like the filled one, and that is the point.

When should I flatten, and when not?

Flatten when the form is final and leaves your hands: a landlord, an employer or a portal asks for a flattened PDF; a recipient says your fields arrive empty (some viewers draw fields badly, and flat answers are page content every viewer shows); you are archiving a filled form to read in 10 years.

Do not flatten yet when someone else still has to fill or sign their part, when you have no fillable copy saved, or when the file carries a certificate-based digital signature that must stay valid. Flattening writes a new file, and any change to a digitally signed file ends that signature’s validity; getPDF says so in the result when the input was signed.

Flatten also does nothing useful to a form you have not filled: the empty boxes become empty boxes on the page, for good. The result line looks the same as for a filled form, so fill first.

What flattening does not protect

Flattening stops casual and accidental changes. It is not a lock in any stronger sense:

• It is not a password. Anyone with the file can read it. For a form with your salary or tax number in it, add a password with Protect PDF, which encrypts the file.
• It is not redaction. Text under a box you drew stays in the file and copies out. Taking something out is Redact PDF’s job.
• It does not stop an editor. In getPDF’s own editor the flattened answers become 1 grouped object: it cannot be retyped as a field, but it can be moved, deleted or covered. Anyone determined, with any PDF editor, can do the same.
• It does not prove anything. Proof that a document was not changed after signing takes a certificate-based digital signature, which getPDF does not make today.

The full threat-by-threat table is in what flattening protects.

The honest part: what Flatten does not do here

• Full XFA forms are not flattened. Some government forms use XFA, an older Adobe-only format, and show a “Please wait” page outside Adobe Reader. Flatten PDF warns: “is an XFA form (the older Adobe-only kind). Its fields are not flattened; fill and print it to PDF in Adobe Reader instead.” That advice is the honest route. A form that has ordinary fields next to an XFA copy, such as the IRS W-9, is different: fill it in the editor and use Save flattened PDF, which takes the XFA copy out and flattens the fields.
• There is no undo after saving. Inside the editor every change undoes until you save; once the flat file exists, the fields are gone from it. That is what the -edited copy is for; change an answer in a filled PDF covers the fix when you need one.
• A note’s text goes, its icon stays. Flattening removes the words of sticky notes from the file and leaves the note icon drawn on the page. Delete notes in the editor first if even the icon should not show.
• Attachments, layers and document properties stay. Flatten is about fields and annotations; hidden pages and attachments covers the rest.

Like every getPDF tool, Flatten runs in your browser. The form and its answers are never uploaded, and once you have used a tool with a connection, it keeps working with Wi-Fi off.