Move this email to another folder Emails can be moved to other folders and even to folders in other accounts. Put the mail in the Trash folder. In addition, all functions are available via the context menu. Highlight a single mail in a folder and click with the right mouse button. You will see a context menu like the one pictured at the right.
Most options are self-explanatory.
For more information see Context sensitive menus in the e-mailer in Opera Help. That should be enough to get you started with the Opera email program.