On an Android device: Open WhatsApp and select Menu (three dots)>Settings>Account from the drop-down menu. Go to Privacy > Choose Last Seen and Nobody.

Even if you turn off the last seen setting, there's no way to hide your status if you're online or typing.

WhatsApp defaults to displaying the time you last used the app in the Chats window, such as today at 6:15 PM. If someone starts a chat with you, they'll be able to see when you last used the app (unless you're currently online, in which case your status will say online). Even if you turn off the last seen setting, there's no way to hide your status if you're online or typing.

However, if you don't want your last seen time to be shown to your contacts, you can disable this setting temporarily or permanently.