When you link your WhatsApp account on an Android tablet, the app syncs up to two years of your most recent conversation history. If you want to search for old messages, use your primary phone.

Open WhatsApp on the phone that is presently registered with WhatsApp and scan the QR code and your second smartphone or tablet will give you access to the same WhatsApp.

Thankfully, you can now link multiple devices to the same WhatsApp account. Even better, your phone doesn't have to be connected to the internet anymore to use WhatsApp on a laptop or tablet.