Only the Account Admin can add users to a business account.
1. Go to your Dashboard and select the Account tab in the left navigation
2. Once in the Account tab, select the Users tab in the menu bar in the top middle of your screen
3. Choose to "+ Add New User" on the right of the screen
4. Enter your new user's Email, First Name/Last Name, and select the role you would like them to have (Account Admin, Content Manager or Contributor)