Home » Blog » PDF » Use Effective Methods to Add Signature to Secured PDF Files

Use Effective Methods to Add Signature to Secured PDF Files

Published By Mohit Jha
Nimisha Ramesh
Approved By Nimisha Ramesh
Published On October 16th, 2023
Reading Time 4 Minutes Reading

As we have moved towards a digital platform, users can now use an electronic signature, or eSignature, to sign their crucial PDF files, including secured PDFs. Passwords, encryption, or a combination of the two are used to secure PDF files. Entering the password or decryption key and using your preferred programme to add your signature is the simplest way to sign an encrypted PDF. In this article, we will explore various methods that allow you to add signature to secured pdf files, ensuring both the integrity of the document and the authenticity of your signature.

You might need additional authorization to modify some PDFs. In this case, you must either ask the document’s owner for the permission details or delete the password. Digital documents can easily be authenticated while preventing fraud and forgery with the help of electronic or e-signing solutions.

In this post, we will be talking about a short description of Protected PDF files followed by the manual solution for adding a sign to PDF documents with the help of the Adobe Acrobat Pro application. Apart from this, we have covered a professional solution to add signature to secured PDF files.

Brief Description About a Secured PDF File

A portable document format (PDF) is a standard file type that enables users to access, present, and share files. PDFs provide a space-efficient way to store various types of content, including text, images, and links while remaining accessible across different hardware, software, and operating systems. By scanning physical documents or using computer software, almost any file can be saved as a PDF. 

A secured PDF is a protected version that restricts users from making changes or performing certain actions. Access codes or setting a password can be used to protect the document, ensuring its authenticity. Several firms used this to maintain the integrity of crucial data, restricting to make any modifications. These security measures also protect copyrighted documents.  

At times, it requires making changes and then ensuring that no further modifications are done. But what if the PDF file is protected with a password? Below mentioned are some methods which can be used to insert a sign into PDF files.  

How to Add Signature to Secured PDF Using Adobe Acrobat Pro?

The methods below will show you how to add a signature to a PDF file that has restrictions using Adobe Acrobat Pro DC.

  1. Launch Adobe Acrobat Reader and click Tool > Fill & Sign, or choose Sign > Fill & Sign from the menu ribbon.
  2. To add a sign, choose the restricted PDF file. No Security in the Security Method. To access the file, enter the Document Open or Permission password.
  3. Insert your signature and save the document by selecting Sign > Add Signature or Add Initial.

Read More: Learn How to Add Custom Page Numbers to PDF Documents

Using Automated Tool to Add Signature to Secured PDF 

Sometimes, users encounter difficulties when trying to add a sign a PDF file due to restrictions that restrict users to perform any action. Therefore, the PDF Document Unlocker Software provides a helpful solution to insert sign in multiple restricted PDF documents. This tool has the capability to remove security restrictions from multiple files. The utility helps to remove all the applied securities and allows users to perform actions such as commenting copying, printing, inserting signature and extracting content. Additionally, this tool enables users to effortlessly remove edit protection from PDF files.

Guided Solution to Insert a Sign in Multiple PDF Files

  • Once the tool(s) have been downloaded and installed, use Add File(s) / Add Folder for inserting the Adobe PDF files which are secured.

Add signature to secured pdf

  • By clicking the Change button and selecting the option to either Save or Print the PDF, choose where you want to save the created PDF, then click Next.

set the location folder path to save pdf

  • In order to add signature to secured PDF files, click the Unlock button now.

Add signature to secured pdf

  • The permissions have been changed to “Enable” as you can see now. Select OK.

Add signature to secured pdf

 Also Read: Use 3 Different Methods to Add Text Watermark to PDF


When a user wants to ensure that a PDF file has not undergone such change. They add their signatures to files as a form of security which ensures that there have been no changes made. We have seen that some users do have difficulty applying that to their secured PDF files. In order to make it simple to add signature to secured PDF, we have explained a few methods. Here, we have talked about both manual and automatic methods for quickly adding signatures to a number of PDF files.



Happy Clients






Years of Experience