Quick and easy archive
- In the left hand pane where the mailboxes are displayed, right click on "your email address", select "New Folder" and give it a name ( Archive or similar).
- After a couple of moments, the directory should appear as "Archive (This computer only)"
This means that messages moved to this directory are saved to your computer rather than the mailbox on the server.
- You can now simply drag & drop your older messages from Inbox, Sent items etc into the Archive folder. This will remove them from server and save them on your computer for future access.
MicroSoft instructions for setting up archiving in Outlook
Manually archive
https://support.microsoft.com/en-us/office/archive-items-manually-ecf54f37-14d7-4ee3-a830-46a5c33274f6