Editing your profile
Your profile holds a display name and a phone number. You edit both from account settings on the website, or from the profile screen in the app.
The email address is the address you sign in with, and it is shown to you as read only. You cannot change it from the edit screen.
The phone number is not a way in. It is a way to reach you, and it is released to the other side only after a booking is confirmed. Until then it is yours alone.
A change you save takes effect at once, and is visible in both places: the website and the app read the same profile.