Open WhatsApp
Go to the Chats tab
Tap the three dots menu
Select Settings
Tap Chats
Turn off Keep chats archived
If you want to hide archived chats from the main chat list, archive the chat
On iPhone, swipe left on the chat and tap Archive
On Android, long-press the chat and tap Archive
To view archived chats, scroll to the top or bottom of the chat list and open Archived
To keep a chat hidden, leave it archived and keep Keep chats archived turned on