Open Gmail
Click the search bar at the top
Type `in:all` or `-in:spam -in:trash`
Press Enter
Look for emails without the Inbox label
Open the email you want to view
To find archived mail from a specific sender, type `from:sender@example.com`
To find archived mail with a keyword, type the keyword in the search bar
To move an archived email back to Inbox, open it and click Move to Inbox