In WhatsApp, when you open a chat of a contact, you can see last seen or online at the top.
Last seen shows the time the contact have last used the WhatsApp, and the online indicates that the contact currently has the WhatsApp opened.
By default, both the online and last seen can be seen by any WhatsApp user. And, remember that the last seen can be hidden. But, online can't be.
If you want to hide your last seen in WhatsApp, then here are the steps to do that task on Android:
Everyone - This one is the default option. It means that any WhatsApp user can see your last seen.
My contacts - It means that only your WhatsApp contacts can see the last seen of yours.
Nobody - It means that no one can see your last seen. Keep in mind that if you chose this option, then you too can't see the last seen of any WhatsApp user.
That's all. All done.
Additional Hint: When one contact is typing, the "typing" is shown at the top of the corresponding contact's chat screen OR beneath the contact's name on the "Chats" tab. It is applied to the group chat too. Remember that the "typing" can't be hidden in WhatsApp.
I hope that the information in this guide is useful to you. If it is, share this guide with your friends.
How to Hide Last Seen on WhatsApp