When delegating your calendar, you can determine the level of access that the delegate has to your calendar.
- Full Access- Allows the delegate to open the delegator's account and view, add, and modify the contents of the account.
- On behalf of- Allows the delegate to send messages on behalf of their delegator.
- Send As- Allows the delegate to send messages as if they came directly from the mailbox. This permission is used for shared mailboxes.
You can also assign permissions for a delegate calendar by using Exchange Online and desktop Outlook applications. However, if you want to use delegate mailboxes, shared mailboxes, or shared calendars, you must configure sharing in the Exchange admin center.