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Can’t Sign a PDF Document – Best Ways to Add Signature to Locked PDF

Written By Aswin Vijayan
Mack John
Approved By Mack John  
Published On November 30th, 2022
Reading Time 4 Minutes Reading

User Query: Recently, one of my co-workers send me some PDF files to which I have to add my signature. When I opened the file and tried to sign the PDF. I found that the sign tool is disabled or not working and now I can’t sign a PDF document. Later I got to know that the file has certain restrictions. Now I want to remove it and make my signature on it. So, anyone can provide me with a quick and simple solution.

Like this query, there are certainly multiple queries with different situations and but the end point is that they are unable to add signature to locked PDF. So, through this post, we will be explaining some working and efficient methods to quickly remove signing restrictions from PDF files or simply enable the sign option.

Before moving forward, first of all, we should know that there are different types of restrictions applied to the PDF file and we will get to know why users can’t sign a PDF document.

What are the Restrictions Present in PDF?

  • Launch the Adobe Reader, then open the file and select Properties.
  • Now using the Security tab select “Document Restrictions Summary”.
  • Scan and check all the permissions that are written as “Not allowed” or “Allowed”.
  • Based on the permission checking’s user can see what are the restriction(s) present in the PDF file.

If you see that the sign option is “Not Allowed”, it means that the signature restriction has been applied and now the user can not add signature to locked PDF. Moreover, the user can check whether the Sign symbol option is “Greyed Out” which signifies that the user cannot sign that PDF document.

Use The Best Method to Avoid Can’t Sign a PDF Document Problem

To unlock multiple PDF files for adding a signature, we generally suggest using a reliable and advanced solution like the PDF Password Protection Removal Software which is a better solution for unlocking and adding signs in locked PDF files. The software basically remove permission password from PDF (Copy, Edit, Print, Extract Text, Comment, Form filling) from the documents.

For Windows OS  Users:

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For Mac OS Users:

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Apart from this, it is capable of removing user-level password protection from PDFs and can be used on both Windows and Mac users.

How the Tools Help in Removing the Can’t Sign a PDF Document Issue?

  • Download and install, then use Add File(s) / Add Folder(s) to insert PDF files.

can't sign a pdf document

  • Now, check and add the password for the required files and choose to Save or Print the signed PDF file.

enter password and choose to save or print them

  • Using the Change button to specify the location path for PDF file saving.

changing the path to save file

  • Now, it will show all the permissions as Disabled, now click the unlock button to add signature to locked PDF.

can't sign a pdf document

Note – This solution is an ideal one for those who have multiple PDF files to unlock and add a signature in all the PDF files. For some countable PDF files, you can use the manual process (Using Adobe Acrobat Pro DC Application).

Solve The Issue Can’t Sign a PDF Document Using the Adobe Acrobat Pro DC

This method is useful for those who have the Adobe Acrobat Pro DC application and want to add a sign to a locked PDF file. Else they can go with the first method that has been explained above.

Guided simple steps, follow the steps properly to remove security and add sign to PDF files.

  • First, using Adobe Acrobat Pro choose & open the file.
  • Now select Fill & Sign option, then press the Sign option and press the Add Signature option.
  • A pop-up message with 3 options will come (Type, Draw, Image.)
  • Select the one you want to and hit the Apply button.

Also Read: Know-How to Extract Images from Secured PDF Documents in Bulk


Before PDF format was introduced, people used to deal with physical papers and use to sign on them. But when people started using the PDF format. It also provided the option to sign digitally for sharing and keeping them secured.

However, at times users can’t sign a pdf document that they receive as the secured PDF files don’t allow others to sign a PDF. So to unlock the file and insert the signature, we have mentioned a manual method (using Adobe Acrobat) and a quick and efficient solution to let the user add signature to locked PDF