End users can delegate their Exchange mailbox or mailbox folders in the Web Console without having to delegate access on the Exchange server.
To delegate, an end user must have the Sharing capability on the Exchange virtual client where the Exchange mailbox is configured.
The users and the user groups that you delegate the mailbox or the folders to can use the mailbox to read and send emails.
In order to use this feature, the users or user groups must be assigned the End User Access permission.
In an Exchange Online (Through Azure Active Directory) environment, delegation of Exchange mailbox or mailbox folders in the Web Console is not supported.