Assign a comment to a user using google docs...

See below

Now, when you click in the search box you’ll see a range of options, including:
 

• Suggested search queries: Click on a term to search for it. 
• Your top collaborators: Click on a person to search for files that you’ve collaborated with them on. 
• File types, edit history, priority items, and more: Click to show files that match the highlighted criteria. 

These filters will help you find and filter content more quickly and efficiently in Drive.