You can delete all the email messages from your Inbox in just a few steps.
Sign in to outlook.office.com. Need help signing? See How to sign in to Outlook on the web.
Select Mail
to display your emails.Hover over your Inbox and select More
>Empty.
All the email in your inbox will be moved to the Deleted Items folder.
To permanently delete the messages, go to Deleted Items and select More
>Empty.
See also
Organize your inbox with Archive, Sweep, and other tools in Outlook on the web