Using New Outlook on Windows for professional communication and productivity
The old-fashioned way to go about this is to get the Microsoft 365 30-day free trial; it includes Classic Desktop Outlook. Use Outlook to move your .PST data into your Outlook.com mailbox and verify it all gets there, then cancel the subscription before the end of the 30-day trial period.
This is helpful, thanks. Is there a way to move IMAP emails coming into my other mailboxes to the PST data now stored in my Outlook.com account? As far as I can see I can only store them in subfolders in the mailbox to which the emails have been addressed.