As title…
There are two possible ways to reach this, and I suspect they both hook up to the same system functions behind the scene in regards of username, though some differences are noticable in other areas - thus I’ll mention both to you. Go to plex.tv, click the “My account” link at the top right corner. Or, go to Plex Web and click on your profile picture at the top right corner and then on the dropdown chose Account.
Thanks, That obviously worked!