Although there are several methods to uninstall an App from an iOS device, this method is useful since it gives you the option to either Delete or Offload the App.
From the Settings ,
1. Tap on General
2. Go to iPhone Storage
3. Select WeChat from the list of installed apps
4. Select either “Offload” or “Delete App”
When you select this option, all data associated with the app remain on the phone. In future if you plan on reinstalling the app, its data will be restored. An offloaded app icon will appear on the homescreen along with a small cloud icon on the side(). When you tap on the icon, the app will be automatically reinstalled.
When you select this option, all data associated with the app will also be deleted. If you do not intend to use the app in future, this is the best option. You can tap on Delete App. Tap again on Delete App to confirm and the app will be removed completely.