Extra: Take Out the Trash
Say the Inbox is stuffed and it is time to get rid of some of the clutter. Here are the steps to delete an item in Outlook. Then, we'll empty the Deleted Items Folder.

Try it: Delete Something in Outlook

Go to the Inbox. Select any sample message.
Go to Home->Delete->Delete.
The deleted message will be moved to the Deleted Items folder.

Try This, Too: Empty the Deleted Items
select the Deleted Items folder.

Go to Folder ->Clean Up->Empty Folder.

What Do You See? You will be prompted that everything in the Deleted Items folder will be permanently Deleted.

Click Yes. The Delete the Deleted Items.