PDF Editing Issues

How to Fix Unable to Sign the Last Page of a PDF in Adobe Fill & Sign

Huma Ashraf Ch Oct 23, 2026 868 views

Question details

The user needs to troubleshoot an issue where they cannot apply a signature or date to the final page of a PDF document.

How to Fix 'Unable to Sign the Last Page' in Adobe Fill & Sign

Product: Adobe Fill & Sign / Acrobat Reader
Device & OS: Mobile phones and tablets
Scenario: Attempting to electronically sign and date the final page of a PDF document using a mobile application.
Observed behavior: The mobile app prevents the signature from being placed on the last page, despite potentially allowing signatures on other pages of the same document.

Before you start

Ensure your Adobe Fill & Sign or Acrobat Reader app is updated to the latest version on your mobile device to rule out known application bugs.

Solution 1Recommended

Determine if the Issue is Document-Specific or App-Related

Isolating the problem by testing different files and devices helps identify whether the issue lies within the specific PDF's permissions or a glitch in the mobile app.

PDF signing issues on mobile devices often stem from either a corrupted form field on a specific page or a localized bug within the app. By testing the document's behavior in different environments, you can narrow down the root cause.

Test signature placement on other pages

Open the problematic PDF in the mobile app and attempt to place your signature on the first or second page to see if the restriction applies only to the final page.

Test a completely different PDF file

Open another known fillable PDF document in your Adobe Fill & Sign app and try to sign its last page. If it works, the issue is isolated to your original document.

Open the file on a desktop computer

Transfer the problematic PDF to a PC or Mac and open it using Adobe Acrobat Reader DC. Try to sign the final page there to determine if the issue is strictly limited to the mobile application environment.

Determine if the Issue is Document-Specific or App-Related

Why test on desktop?: Desktop versions of PDF readers handle complex form fields and certificate-based digital signatures better than mobile apps. If it works on desktop, the mobile app likely lacks support for that specific field type.

Solution 2

Verify PDF Security and Form Field Properties

Check if the document has restricted editing permissions or invisible overlapping form fields that block mobile signature tools.

Easily Sign Any Page of Your PDF Using WPS Office

Avoid mobile signing glitches and form restrictions. WPS Office provides a powerful PDF reader and editor that lets you smoothly add electronic signatures to any page, across all devices.

1. Open your PDF in WPS Office: Launch the WPS Office application on your mobile device or computer and open the PDF document you need to sign.
2. Access the PDF Signature tool: Navigate to the 'Fill & Sign' or 'Edit' tab located in the bottom or top toolbar, and select the 'Signature' option.
3. Create or select your signature: Draw your signature directly on the screen, type it using the keyboard, or insert an existing image of your signature.
4. Place the signature on the last page: Scroll down to the final page of your document and tap exactly where you want the signature to appear, then resize it as needed.

Sign anywhere on any page without restrictionFully compatible with standard Adobe PDF formatsCross-platform support for mobile, PC, and MacFree and lightweight alternative for document editing

Frequently Asked Questions

Why does my mobile PDF app block me from signing the last page?

This usually happens due to form-specific field restrictions, hidden security settings that restrict document changes, or a localized bug within the mobile app's rendering of the final page's layout.

Can I sign a secured PDF on my phone?

If the PDF creator has locked the document with a permissions password prohibiting filling or signing, you cannot sign it on mobile or desktop until the document password is removed.

What should I do if the signature box is unclickable?

Try tapping slightly outside the designated signature box. Sometimes, pre-configured digital signature fields (meant for secure certificate-based signing) block standard draw-to-sign tools on mobile apps.

PDF Troubleshooting