1. Open your favorite web browser. ( Chrome, Safari, Firefox, Edge)
  2. In the url address simply type portal.office.com and sign in with your windows credentials.
  3. Then select your profile picture in the top right corner
  4. Now select the open another mailbox and start typing the email address of the shared mailbox that you have access to read and manage
  5. This should open a new window and you can start viewing anything older than 12 months
  6. When finished close window and log out of your session and let the IT department know when you are finished accessing the mailbox to disconnect your session.