How to Make a Fillable PDF Not Fillable (Lock Your Form)

How to Make a Fillable PDF Not Fillable

To convert a fillable PDF into a static, non-fillable document, you need to flatten it. Flattening merges the interactive form fields into the PDF's background layer, turning editable text boxes, checkboxes, and dropdowns into fixed images. The fastest method: open your filled PDF, print it to a new PDF file, and the result is a completely static document that no one can edit.

Here's every method to do it, from free built-in tools to professional workflows.

Why Make a Fillable PDF Not Fillable?

Before choosing a method, it helps to know why people lock fillable PDFs. The reason matters because some methods handle certain scenarios better than others.

1. Prevent Edits After Submission

The most common reason. You've filled out an application, tax form, or contract and need to send it to someone. If you send the fillable version, the recipient can modify your answers. Flattening locks everything in place.

2. Ensure Consistent Display

Fillable PDFs render differently depending on the viewer. Font substitution, field borders, and spacing can shift between Adobe Acrobat, Chrome's built-in viewer, and Preview on Mac. A flattened PDF looks identical everywhere because the text is baked into the page.

3. Reduce File Size

Form fields add metadata, JavaScript, and font resources to a PDF. A fillable form can be 2-5x larger than the same document flattened. If you're emailing completed forms or archiving them, flattening cuts the bloat.

4. Prepare for Printing

Some printers mishandle form fields, producing blank spaces where filled data should appear. Flattening eliminates this risk entirely.

5. Remove Sensitive Form Metadata

Fillable PDFs can contain hidden metadata: field names, validation scripts, submission URLs, and even previous values. Flattening strips all of this, leaving only the visible content.

Flattening vs. Removing Fields: What's the Difference?

Most guides use these terms interchangeably. They're not the same.

Flattening converts field data into static text on the page. If you filled in "John Smith" in a name field, flattening stamps "John Smith" as permanent text and removes the field. Your data stays visible.

Removing fields deletes the form fields entirely, including any data entered in them. If you remove a filled name field, "John Smith" disappears from the page. You're left with an empty form.

If you've already filled out the form and want to keep your answers, flatten. If you want a clean, empty, non-fillable version of the form, remove the fields.

Method 1: Print to PDF (Free, Works Everywhere)

This is the simplest and most universal approach. It works on Windows, Mac, Linux, and even Chromebooks because it doesn't require any special PDF software.

On Windows:

1. Open the filled PDF in any viewer (Acrobat Reader, Chrome, Edge)
2. Press Ctrl + P to open the Print dialog
3. Select Microsoft Print to PDF as the printer
4. Click Print
5. Choose a filename and save location

On Mac:

1. Open the filled PDF in Preview or any application
2. Press Cmd + P to open the Print dialog
3. Click the PDF dropdown in the bottom-left corner
4. Select Save as PDF
5. Choose a filename and save

In Chrome (any OS):

1. Open the PDF in Chrome's built-in viewer
2. Click the Print icon or press Ctrl/Cmd + P
3. Change the Destination to Save as PDF
4. Click Save

The output is a flat PDF. All form fields are gone, and the filled data is permanently embedded as static text.

Limitation: Print to PDF may slightly alter the document's visual quality. It re-renders the page at the print resolution, which can affect sharp vector text. For most forms, the difference is negligible.

Method 2: Adobe Acrobat Pro

Acrobat Pro offers two precise methods that preserve the original PDF quality better than printing.

Option A: Flatten Fields via Prepare Form

1. Open the PDF in Acrobat Pro
2. Go to Tools → Prepare Form
3. Right-click on any field and choose Select All
4. Right-click again and select Flatten Fields
5. Save the document

This converts every field to static text while keeping the rest of the PDF untouched. The document quality is identical to the original.

Option B: Remove Fields Entirely

If you want an empty, non-fillable version:

1. Open the PDF in Acrobat Pro
2. Go to Tools → Prepare Form
3. Right-click any field → Select All
4. Press Delete
5. Save the document

This deletes the fields and any data in them, leaving blank spaces where fields used to be.

Method 3: Preview on Mac (Free)

Mac's built-in Preview app can flatten PDFs through the print workflow.

1. Open the PDF in Preview
2. Fill in any remaining fields
3. Go to File → Print (or press Cmd + P)
4. Click the PDF button in the bottom-left corner
5. Select Save as PDF
6. Save with a new filename

The saved PDF is fully flattened. All form fields become static content.

Note: Preview doesn't have a direct "flatten" or "remove fields" command. The print-to-PDF workaround is the only way.

Method 4: Free Online Tools

Several online tools flatten PDFs without requiring any software installation.

Smallpdf (smallpdf.com):

• Upload your PDF
• Choose to flatten the entire document or only form fields
• Download the result
• Free for limited daily use

Sejda (sejda.com):

• Upload the PDF
• Select "Flatten" from the tools menu
• Process and download

iLovePDF (ilovepdf.com):

• Upload your file
• Use the PDF editor tools, then export
• Flattened output available on download

Limitations of online tools:

• Your PDF is uploaded to a third-party server (privacy concern for sensitive documents)
• File size limits on free tiers (typically 5-25 MB)
• Daily usage limits on free plans
• May add watermarks on free versions

For tax forms, medical documents, or anything containing personal data, consider an offline method instead.

Method 5: Fill and Flatten in One Step

If you haven't filled out the form yet, you can save time by using a tool that fills and flattens in a single step.

AutoFillPDF does this automatically. Upload your form, provide your data, and the output is a completed, flattened PDF. There's no extra step to lock the form because the result is already static—no form fields, no editable layers, just a clean PDF with your data in place.

This is especially useful when processing multiple forms, since you don't need to fill each one and then separately flatten it.

Comparison: Methods for Making a PDF Not Fillable

How to Verify Your PDF Is Actually Flat

After flattening, confirm the form fields are gone:

1. Open the new PDF in Adobe Acrobat Reader
2. Go to View → Tools → Prepare Form (if available) or hover over where fields were
3. If no blue highlights appear and you can't click into any fields, the PDF is flat
4. Try selecting text where a field used to be—if it selects as part of the page text, it's been flattened

Alternatively, check the file size. A flattened version should be noticeably smaller than the fillable original.

FAQs

Can I undo flattening and make a PDF fillable again? No. Flattening is a one-way process. Once fields are merged into the page, there's no way to extract them back out. Always keep a copy of the fillable version before flattening.

Does Print to PDF preserve the filled-in data? Yes. When you print to PDF, everything visible on the page—including text you typed into form fields—is captured in the output. The data stays; the fields don't.

Will flattening affect my digital signatures? Flattening removes signature fields along with all other form fields. If the document has been digitally signed, flattening breaks the signature validation. Flatten before signing, or sign the flattened version.

How do I flatten only some fields and keep others editable? In Adobe Acrobat Pro, you can select specific fields (hold Ctrl/Cmd and click each one) instead of selecting all. Then right-click and choose Flatten Fields. Only the selected fields will be converted to static text.

Is there a difference between "locking" and "flattening" a PDF? Yes. Locking (password protection) restricts editing but keeps fields interactive—someone with the password can unlock and change values. Flattening permanently removes the fields. If you need absolute certainty that no one can alter the data, flatten rather than lock.

Can I remove fillable fields from a PDF on my phone? Yes. On both iPhone and Android, open the PDF, use the Share or Print function, and select "Save as PDF" or "Print to PDF." This produces a flattened copy, the same as the desktop method.

Related Guides

• How to Flatten a PDF
• Fill Out a Non-Fillable PDF
• Edit PDF Form Fields
• Fillable PDF Not Working