Navigate to Settings > Staff and click New Staff User at the top right:

Add their details:

You can untick Full Permissions and you'll then have the option to restrict their permissions further: 

Only staff users with Full Permissions ticked will be able to see the Profitability section, they will also be able to see all users Notifications if they click the bell at the top right of the page and select Notification Manager.

• If you are unable to see the Staff option when you hover over Settings this will be because your account has the permission "Hide Staff Page" turned on. If you need to amend this permission you will need to contact your account administrator.