By default, your community username matches your First and Last Name [username]. However, you can change the username that is used in the Public Sector Community, without affecting your email login credentials.
To update your community username, click on your username in the right corner of the global header to open your user menu, and select My Settings:
On the My Settings > Personal > Username tab, you'll find your username listed. Click into the field to update your username. You can use letters, numbers, dashes, or underscores, but you cannot use period or other special characters.
Once you have entered your new username, click Change Username.
@Rohit_Bhaskar , I don't seem to have the "username" option when I go to My settings->Personal
@Rohit_Bhaskar - I have the same issue than Jason. How can I change my Username in the Community? I would prefer to have my First Name + Last Name to facilitate members to recognizing me 🙂