To improve the email performance, delete unwanted emails from Outlook 365. If you are Unable To Delete Emails In Outlook 365, consider the following solutions.
Purging the emails:
Modify the Retention policies:
Set the automatic delete:
To change the email address, open the Email application.
Emails that you have deleted will be in the trash..
To archive the emails first, sign into the Gmail account.
First, log into the account and extend the side tab..