Assign delegate access using the Outlook desktop app for Windows

Overview:
Delegate access allows someone else to act on your behalf in relation to email messaging and accepting, declining, or creating meetings. For someone to be a delegate, you need to provide them permission. It is not recommend to have more than one delegate for the same account.
 
Assigning Delegate Access:
  1. Open Outlook
  2. Select File | Account Settings | Delegate Access.

     
  3. Click on the Add button.

     
  4. Type the person's name you wish to add, click the arrow key to search, select the name, and click the Add button.
  5. Click OK
  6. On the "Delegate Permissions" screen, select the desired permissions for each of your folders (Calendar, Tasks, Inbox, Contacts, Notes and Journal). Choose from the following Permission levels:

None — (Delegate has no access to the folder)
Reviewer — (Delegate can read items in the folder, but can't make changes)
Author — (Delegate can read items and create new items in the folder)
Editor — (Delegate has full access to read, create, and modify items in the folder)

  • If you want your delegate to receive copies of your meeting-related notifications (so that the delegate will also be notified of any new meetings and can "Confirm" or "Decline" meetings on your behalf), grant Editor permissions and click the check box Delegate receives copies of meeting-related messages sent to me.
  • If you want to send a notification message to your new delegate, click the check box Automatically send a message to delegate summarizing these permissions.
  • If you want your delegate to be able to see your private items, click the corresponding check box.
  • If you want the delegate to be able to "Send On Behalf of" you but not see details in your calendar or Inbox, you can add them as a delegate and select None for permissions to various folders. 
  1. Select your option for how to deliver meeting requests (My delegates only, but send a copy of meeting request and responses to me (recommended), My delegates only, My delegates and me)
  2. Click OK
  3. Click OK.

Once delegate access has been configured, you may want to share your mailbox, inbox, and subfolders with your delegate. Refer to How to share my mailbox, inbox, and subfolders using the Outlook desktop app for Windows?