In the dashboard menu on the left you’ll find the header ‘Users’. Here you can find a list with all users that are allowed into the dashboard environment as well as add new ones using the ‘Add new’ button. You’ll get to see a form with a few input fields, username (required), email address (required), first name, last name and website. You can choose to leave the checkbox selected, which triggers an email to be sent to the new user.
You can also modify the role of the user, it’s important to check which permissions the user should have (is the user allowed to edit posts and pages or not?).