This screen is solely for the purpose of using your real name in various places within the system and with your colleagues. What you enter here is just to make your My Clients Plus experience more personal.
Don't worry, this has no effect on billing or any of your other information from your Practice Setup.
If you enter your email address and/or mobile phone number here (recommended), the system may use them to let you know about To-Do items or other things specifically related to your username in future software releases.
Some specifics...
The Note Addendum in Progress Notes will show the name associated with the username rather than the username when the Username Preferences is completed:
If the Username Preferences is not completed, then the username is displayed in the Note Addendum: