Change the name shown to teammates on Settings → Profile. This is your user name, not the workspace name.
Update your name
Open Settings → Profile.
Edit first name and last name.
Save. The page flashes "Profile saved."
The header shows your name, the current workspace badge, and your role. Those workspace badges are context. They do not rename the workspace. Owner or admin renames the workspace on Settings → General.
Email stays as sign-in
The Email field is your sign-in email. You can copy it. The line under it says "This is your sign-in email. Changing it is not available yet."
Password and Sign out live further down on the same page. They have their own article. Changing the profile name does not change billing, seats, or the workspace timezone. Those stay on Billing and Settings → General. Teammates see the new name on Members and in Unibox assignment after you save.