Like in all previous version of Windows, your local or Microsoft’s account name is displayed on the login screen and on the top-left side of the start menu. If you are not happy with your username you can easily edit it and change the way it is displayed.
Method 1 of 2
Change your Microsoft account name in Windows 10
NOTE: In order to rename your Microsoft account, your PC must be connected to the internet.
IMPORTANT: This method will not rename your Microsoft account email address, and will only change the display name that you see on the Start menu as well as on the login screen.
Step 1: Open settings app by accessing the start menu and then clicking Settings on the left hand side.
Step 2: Now click on Accounts.
Step 3: Click Your email and accounts.
Step 4: Now click on Manage my Microsoft account. This will direct you to a link which will open in your default browser. You might be asked to enter the password, enter the password of your of your Microsoft account and sign in.
Step 5: Click Edit Name which will appear on the left side below the account display picture.
Step 6: Now you will see the page where you can easily edit the Microsoft account display name. When it’s done, click save.
Method 2 of 2
Rename your local user account name in Windows 10
Step 1: Open Control Panel.
Step 2: Click User Accounts.
Step 3: Click on Manage another account, this will show all local as well as Microsoft accounts on the PC. Click on the user account you want to edit.
Step 4: Now click on the Change account name and enter the new name. Click Change Name button and the new name will be saved.