We all know that how to mark read mail as unreadon Gmail web but when it comes to do in app somewhat different and not an easy for first time users. So I am going to show here how mark all email as read in gmail or read mail as unread on Gmail Android. You can mark any read mail as unread at anytime from app.
Like this you can mark all emails as read or unread on Gmail Mobile app like android, ios or windows versions.