Note that you'll need to be Owner or Manager level user to have access to User Accounts.
The number of User Accounts isn't limited and here's how you can invite others to manage content too:
- Click 'Settings' from menu.
- Select the tab 'User Accounts'.
- Type the invitee's email in the 'New user email' field.
- Choose the invitee's user role (Manager or Editor). The 'manager' role has access to most of the site features including user management. The 'editor' role has access to a selected section to manage and publish posts.
- If you chose Manager, just click 'Invite user' button and the invite will be sent to the invitee's email.
- If you chose Editor as user role, you need to select one section from the dropdown. Then click 'Invite user' and the invite will be sent to the invitee's email.