The Profiles tab allows you to sign in users and create guest users on a console.

You can toggle an existing user’s state in two ways:
Signing out a user will automatically sign out all guest accounts associated with that user. Signing out a guest user will remove the guest user from the user list.
You can remove a user from the console by right clicking on the user and selecting Remove User From Console. This will remove the user from the list of users in the Profiles tab and from the list of users on the console itself.
You can set a default user by right clicking on a user and selecting Set as Default User. Setting the default user will cause that user to automatically sign in each time the console boots. The default user is indicated with an asterisk next to the user name.
You can sort the user list by clicking the Gamertag, Email, or Status column headers.
There is a limit of 16 signed in users on a console. This total includes all users and all guests. The +USER and +GUEST buttons will be grayed out once the limit is reached.