Step 1
Click the Facebook link to view its associated Facebook profile. The Facebook ID of the profile is the portion of the Web address displayed in your browser's address bar between "facebook.com/" and the first question mark. If you see no question mark, the ID is everything after "facebook.com/" without the quotes.
Step 2
Click the "Info" tab below the profile picture on the left side of the screen while logged in to your Facebook account to navigate to the user's basic information.
Step 3
Scroll down to the bottom of the screen to view the "Contact Information" section of the Info screen. If the user has made her phone number visible to you, it appears to the right of "Phone.