WhatsApp disappear on my iwatch , why ?

Hi

The WhatsApp Messenger app for iPhone does not include an Apple Watch app, so it will not be shown when searching for apps via the Watch app on your iPhone.

https://itunes.apple.com/us/app/whatsapp-messenger/id310633997?mt=8

If you are no longer receiving notifications on your watch from WhatsApp Messenger, the following steps may help:

If you have not yet done so, update your iPhone and Apple Watch to the latest software, starting with your iPhone:

• Update the iOS software on your iPhone, iPad, or iPod touch - Apple Support
• Update the software on your Apple Watch - Apple Support

Update WhatsApp Messenger on your iPhone to the latest version (an update was released on 19 October):

• On your iPhone, in the App Store, tap on the Updates tab > install any available app update.

Keep in mind that how notifications behave depends on the status of your devices and your settings. With Wrist Detection enabled, in order to bring notifications to your attention as soon as possible:

• If your iPhone is unlocked, you will receive notifications on your iPhone instead of on your watch.
• If your iPhone is locked or asleep and your watch is unlocked (regardless of whether the watch screen is asleep or awake) and on your wrist, you will receive notifications on your watch.
• If your watch is locked or has Do Not Disturb enabled, notifications will go to your iPhone.
• More information: Notifications on your Apple Watch - Apple Support