Hiding a chat doesn’t mean deleting the chat or backing it up to your SD card. But it will just be hidden on WhatsApp.
Here’s how to hide chats temporarily:
Step 1: Long-press on the chat you want to be hidden on WhatsApp and it will show Archive box on the top.
Step 2: Click on that box to hide your chat.
The archived chats, individual or group, will remain hidden even as you get a new message in them.
You won’t be notified for archived chats unless it’s you who is mentioned or replied to.
Here’s how to undo ‘hidden’ chats on Android:
Step 1: Go to the end of the chats by scrolling down.
Step 2: Click the Archived section when you find it and you will get to see all the hidden chats.
Step 3: In case you wish to see the hidden chats at the top again, click on the Archive box again after long-pressing that chat.
Here’s how to “permanently” hide chats:
Turn on the “Keep chats archived” feature by going in Settings > Chats > Archived Chats > Keep Chats Archived.
Every chat you selected after this setting change will be hidden forever. However, WhatsApp includes an Archived box on top of all your chats and then you can remove the box as and when you wish.