The only details provided during your account creation that you can change on your own are:
Username
Phone number
Be careful that changing the details above have a limited number of times; which after that, you will need to contact the customer support team
The details provided during your account creation that you cannot change on your own are:
First name
Last name
Email address
You will need to contact the support team via email or chat support if you want to proceed with any change, and if the reasoning is not clear enough, the request might be denied.