Some document requirements may be covered on external website, and a link to the website would be more suitable evidence than a .pdf or a .docx file. In these cases, you can use the Add link feature. 

Procedure

1. The Add link button is at the top of the page: 
    
   
    
   
2. After clicking Add link, you can then add the link and fill out the rest of form
    
   
3. Then click Save