Why is my Name showing in Emails?

Why is my Name showing in Emails?

I have signed up for my primary account using web@mydomain.com
and created a secondary user named shop@mydomain.com.

I edit both profiles so the Full Name and Nickname are the same.

My PRIMARY account is sending with Name my full name from signing up, not what is in settings. Is it required that every user has their real name? Where do I change the settings? What if I have more than one person using the email?

For example: If I have support@mydomain.com and then my sister and I are doing support- would it not be weird if she is signing emails that are coming from my name? Is there no way to use an account as a generic mailbox?

I already went to Account Settings on both accounts and edit the profile. It looks updated, but not updating when send. What should I do next?