If you do not need to take any action with an email, or have already actioned it (is attached to a contact and/or work timeline and/or assigned to a to-do list) you should clear it from triage.
Click on the clear icon from your email actions menu
When an email is cleared from Triage, it will be located in your Cleared Items, found from your main menu.
The email will also be archived in your regular email inbox. For Gmail, they will be archived in an "All Mail" folder and for O365 and Microsoft Office, they will be archived in the "Archive" folder.