What are some of the restrictions imposed by Windows 10 on the user name?

What will be an ideal response?

When creating new users, you must be aware of the restrictions imposed by Windows 10 on the user sign-in name, such as the following:
* User names must be unique-No two users can have the same sign-in name, because the sign-in name is used by the computer to identify the user and verify the password associated with it during sign-in.
* User names must be 20 characters or less-This restriction is typically not a problem, because no users want to type in a sign-in name of 20 characters or more.
* User names are not case sensitive-You cannot change the case of letters to create unique user sign-in names; Windows 10 will read any case changes as the original name. Also, users do not need to be concerned about case when they type in their user name. However, passwords are case sensitive.
* User names cannot contain invalid characters-Windows 10 uses some characters for special functions, so they cannot be used in user sign-in names. The invalid characters are: "/\{}:;|=,+*?<>.