- Open Exchange Admin portal. outlook.office365.com/ecp
- On the left click Recipients
- On the right click Mailboxes
- Double click user’s mailbox that you want to share
- On the left click Mailbox Delegation
- On the right, scroll down to Full Access, and add the account to whom you want to give access
- Click Save
- Open Outlook of the person to whom you gave access
- click File, Account Settings, Account Settings
- Double click mailbox
- Click More Settings
- Click Advanced tab
- Click Add to add shared mailbox
- It can take up to 2 hours, the shared Mailbox will automatically appear in the user’s Outlook. Close and open the user’s Outlook.