Changing of username provides better flexibility if our existing username is not much readable. We can change the username in Facebook only one time.
Here are the simple steps to change the Facebook username/profile URL -
1. Logged-in to the Facebook.
2. Click on "Lock" icon available to the right-side of "Home" link.
3. A pop-up will open, now click on "See More Settings" link available on it.
4. Now click on "General" link available on the top - left side.
5. Click on "Edit" link available in front-of username.
6. In the available textbox, Enter your username. Facebook will automatically check if this is available or not.
7. If username is available then Enter your password in password textbox and click on "Save Changes" button.
Your username successfully changed. Enjoy:)
Note:- Your username can only be changed once and should include your real name.