How to view archived mails in gmail app?

Actually, Gmail does not have a separate folder for 'Archived' mails. This is why many people get confused. When you archive an email, it is simply removed from your Inbox view.

To find it, you just open your Gmail app. Tap on the three lines menu at the top left. In the list, you will find 'All Mail'. Your archived email will be inside this folder, along with all your other mails.

Another easy way is to use the search bar at the top. If you remember the sender or any word from the email, just type it in the search. The mail will show up from the archive. Hope this helps you.