Bulk Actions. Multiple chats can be pinned, muted, archived or deleted in one tap.

Press and hold a chat in your list to select it, then tap any others you'd like to include. You can also drag pinned chats to change their order.

On Android, the ➕ menu has more options like mark as read or add to folder.

On iOS you can do the same by tapping the Edit button in the top left corner.