What will you do if you do not have the username of the person you want to search for on your Facebook? There are many users who exist with similar names. In this case, what will you do because it will be a little bit tougher to find someone with their name only without their username? In this case, Facebook allows you to search for people via their phone numbers if the person has associated their number with the account. To find someone by phone number on Facebook, type the number of the person in the search bar and see what is showing up on the screen. If your luck is doing well with you, you will get the person in the search result. Also read here how to recover deleted Facebook messages in some easy steps.