If you want to change username of a local account, log in via Administrator user account created at the time of setting up (or installing) Microsoft Windows 10 Operating System.
Press Windows and “R” keyboard buttons together to run this command;
Next select the local user account from the list you wish to change the name and click “Properties” option;
In the new window, change the name under “User name” and enter other details (optionally) under Full name and description;
When done, press OK and restart your computer.