• Account (from More) holds Appearance, Menu, Rest timer, Warm-up sets, Plan setup, Starter library, username and password.
• Change username gives you a new name: type it and your password. Your friends, chats, coaches and everything you've logged stay as they are; from then on you sign in and are found with the new name. It needs a connection.
• Change password signs you out on your other devices.
• Delete account permanently removes everything: exercises and history, routines, meals, measurements, tasks, chats and coaching. It can't be undone.

Related

AppearanceBackground, accent colour and text size, previewed as you choose.Finding your wayToday, then the tabs you choose; You (your picture) for everything else.Rest timerCounts down your rest after every set; set the − and + amounts to your liking.Warm-up setsLighter sets before your first working set, worked out for you and never saved.