Select the File tab at the top of the screen and then Options
If it doesn't need to be retained, just go ahead and delete. If an email must be retained, keep it in a folder in Outlook for easier access. Hiding and forgetting about emails does not elimnate your responsibility for them. Records Management does NOT advise using the option to move old items to a default archive folder. In the Properties dialog box, go to the AutoArchive tab and select your desired settings. Right click the folder you would like to delete from and select Properties. See here for more guidance on which emails must be retained.