How to Create Facebook Username?

STEP 1 - Login Your Facebook Account [Facebook]

STEP 2 - Go To Account And Select Account Settings 

  

STEP 3 - In Account Settings you can see User Name Click on Edit

STEP 4  - Now you can type your unique user name which you want set on your   facebook id [Ex. http://facebook.com/username]

STEP 5 - Now click on Save Changes [***Remember - once you have fix username, you can't remove or change it..so be careful]