As per your screenshot, I can see you actually use MS Team free personal account.
I'd like to let you know when it comes to MS Team free there are 2 types of accounts.
- MS Team free personal account.
- MS Team free organization account.
Please note those 2 accounts are not the same. They are different.
MS Team free personal account only use a mobile number, MS Team free personal account indeed doesn't include the email address.
Please note, it's not possible to delete MS Team free personal life account, you can only disassociate MS Team free personal life account from your email account by visiting the link below then log in with your phone number and remove the phone number as an alias: https://go.microsoft.com/fwlink/?LinkId=529489
So therefore you can't change the email address of MS Team free personal account, what you can change is, the registered phone number. Unfortunately, that's just how MS Team free personal account is designed.
Kind Regards