How to Digitally Sign a PDF Document in Adobe Acrobat Reader?

Here are the steps on how to sign with your digital ID within the Adobe Acrobat Reader application: 

1. Open a PDF document you wish to sign in Adobe Acrobat Reader
2. Once open, a Protected View warning will appear. Click the Enable All Features button at the top
   
   
    
3. There are two ways of signing a document: 
   1. Clicking the signature field if one is added to the PDF document, If a shaded signature field is provided, click the shaded signature field and skip to Step 8 or 
   2. Manually drawing the area where the signature is to be added, continue to Step 4.
       
4. Once the warning goes away, click Tools at the top left, then click Open under Certificates:
   
   
    
5. The Certificates toolbar will appear at the top or left side (depending on the size of the window). Click Digitally Sign:
   
   
6. A pop-up window will appear on how to use the tool. Click OK.
    
7. Using the mouse pointer, click and drag a rectangular area you'd like to sign:
   
   
    
8. A window will appear with a list of signatures if one already exists. Select the desired signature and click Continue.
    
9. Verify the signature details and click Sign at the bottom right to save the signed document.