How to How to apply a sharing policy to multiple mailboxes in EAC (Exchange admin center)

Step 1: Sign into Office admin portal via http://portal.office.com and open Exchange admin center

Step 2: Navigate to Recipients > Mailboxes.

Step 3: In the details pane, the mailbox properties will be configured for bulk edit. Scroll down to click More options.

Step 4: Under Sharing Policy, click Update.

Step 5: In bulk assign sharing policy, select the sharing policy from the list.

Step 6: Click save to apply the sharing policy to the selected mailboxes.