Office 365 (Outlook 2013 / 2016 for Win) - How to Assign a Delegate
1. Click the File Tab and Info. Click Account Settings and Delegate Access.
2. Click Add.
3. Enter the name of the person to designate as your Delegate, or search and select them from the search results. Click Add. Click OK.
4. Accept the default permission settings, or select custom access levels for Exchange folders. By default, the Delegate is granted Editor permissions (can read, create, and modify items) to your Calendar folder. When the delegate responds to a meeting on your behalf, it is automatically added to your Calendar folder.
Note: Checking the "Delegate can see my private items" box allows the delegate to access all of your Exchange folders, including Mail, Contacts, Calendar, Tasks, and Notes so please use caution when selecting this.
5. Click OK. Messages sent with Send on Behalf permissions include both the delegate's and manager's names. When a message is sent with Send As permissions, only the manager's name appears.