The administrator assigns power to new users who will share the computer with the admin. All these actions mean that you will be setting an account with administrative powers, that’s a person who has power to administrate the computer, make system-wide changes, install or refuse updates and applications, and so on. You’ll be able to pick a twee little image from a selection (butterfly, snowflake, billiard ball). You’ll be prompted to enter your name (in fact, any name you want to use), short name and password.
When you purchase a new Mac, you must set it up.
1.1 How to Change Name, Short Name, Password.