How to Share and Access Shared Folders in Outlook for Mac
Shared Mailbox account folders can be accessed through Outlook for Mac within your personal account.
How to grant access to others in Outlook
Sharing must be done using a "top-down" method, where access is first granted to the top level of the account, and then access is granted in a granular fashion to all areas of the account that are needed. This includes Inbox, Sent Items, Cabinet, folders, and subfolders, etc.
Right-click (or hold down the Ctrl key on your keyboard and click) the name of the account in the left-side column and then select Sharing Permissions.
Click Add User and select the person to whom you wish to grant access.
Highlight the user in the list and grant a permission level such as Publishing Editor. Other types of permission can be granted as appropriate, but Folder Visible is mandatory.
Click OK.
Allow access to additional areas of the account individually by selecting them and repeating steps 2 through 4.
If the person you are granting access to is unable to see anything past the name of the account itself when they add the folders to their account, recheck all the permissions for each level of the account to ensure they have been granted as needed.
How to access shared mailboxes and folders
Those who are Full Access Delegates over accounts can add account folders to their personal account directly. Others need to have a Full Access Delegate set sharing permissions before the account can be accessed.
View Microsoft's instructions for opening a shared mailbox or folder in Outlook for Mac.