How do I completely uninstall an app

1) How to delete apps on your iPhone, iPad, and iPod touch - Apple Support

2) Check if you have related subscriptions:--> View, change, or cancel your subscriptions - Apple Support

Regards

Giulio

There is only one way to uninstall an app: Tap and lightly hold on the app in question until they all start to shake, and then tap on the in the corner of the app. This removes it entirely from the device.

More details here: How to delete apps on your iPhone, iPad, and iPod touch - Apple Support