How to get Facebook username.

If you’re testing an app that uses Facebook login, you’ll need to be added as a tester, developer or admin to the Facebook app.

The admin will need your username to add you.

To get your username, first go to Facebook and login.

Then, go to your profile by clicking on your profile button at the top of the page, highlighted in white.

Your username is just the last path in your profile URL as highlighted here.