If you want to input your name, you can. It isn't made public, but it will appear in the top right-hand corner in place of your username when you're logged in.
This is the email address associated with your account. All of your reminders, legit checks, beemails, and any other support-driven messages will be sent to this account, so make sure it's the one you check most frequently!
You can also log in using this email if you forget your username.
We infer this automatically when you create your account. If it's wrong, or if you're moving, or if you're going on a long trip, you can change it anytime and it will take effect immediately. Be wary if it's a big change and your goal deadlines might have hit already in the new timezone! It's probably safest to complete your goals before changing your timezone, but if you run into any trouble, don't hesitate to contact support.