One of the tasks that you will be faced with is granting access to other user's mailboxes. Although this task could be expedited to your help desk by using RBAC, typically changing permissions isn't something that many companies allow to be done by a lot of people.
To complete the following steps, you will need to launch the Exchange Management Shell or log in to the Exchange Admin Center.
In this section we will learn about assigning mailbox permissions.
The following command will grant a user Mark Johnson full access permissions to the mailbox of Ronald White:
Add-MailboxPermission –Identity "rwhite" –user "exblog\mjohnson" –AccessRights "FullAccess"
Assigning full access permissions through the EAC can be done as follows:
Navigate to recipients | mailboxes.
Double-click on the mailbox you want to grant access to.
Click on mailbox delegation.
Click on the plus-sign (+) under Full Access.
Select...