Hi, c. I'm Robinson, and I’m happy to help you today.
You can change the name in two ways:
Option 1: Change the Mailbox Sync Settings
1-Open the Mail app
2-Click on the gear icon in the left bottom corner
3-Click on Manage Account and click on your email account
4-Then click on "Change mailbox sync settings"
5-Scroll down to "Send your message using this name" and change it
6-When finished, click on Done to save the change
Option 2: Reset the mail app and re-configure the email account
1-Click on Start then click on Settings
2-Click on Apps, search for the mail app and click on that
3-Then click on Advanced options
4-Scroll down, click on Terminate and Reset
5-After this, open the Mail app and re-configure your email account
Note: This price will delete all settings in the Mail app, all email accounts will need to be re-configured