To add an account, you should go to the “Devices/Services” tab. First, select the device and click the “manage” button, which is above the devices list. In the new window, click the “add account” button, located in the upper right-hand corner of the main area.
Which account should I add?
You can select from three types of accounts: Apple, Exchange (Office 365), Google. You should add those services accounts, that you are using in your smart phone.