Hi! Sorry to hear about this, canging the passord is a good first step, activate 2-step verification. After this, close all your open sessions:
https://account.live.com/proofs/manage/additional
After this, please review the next link to see if any apps that you don’t know have access to your account and delete them:
Finally, do this in Outlook from Edge:
Sign in to Outlook.com
Click on the gear icon (Settings) in the upper right corner.
Look for and open Mail settings.
Go to the Rules section and check if there are any rules you didn’t create. If there are any suspicious rules (for example: “forward everything to @.___” or “move everything to Deleted”), delete them immediately.
Also check in Forwarding and IMAP and make sure there are no addresses added. If there is one and it’s not yours, remove the forwarding.