Here is how to to stop whatsapp messages popping up or turn it on.
1. Open iPhone Settings
2. Tap Open Notifications
3. Go to WhatsApp and tap it
4. Set the proper notification you want
Here is the main push notifications ,set your preferences for Alert style
Sounds: An audible alert plays.
Badges: An image or number appears on the application icon.
Alerts/Banners: An alert or banner appears on the screen.
You can turn off the vibration or sounds on whatsapp by disabling all the notifications.