1.
See -> Delete apps on your iPhone, iPad, and iPod touch
Delete apps on your iPhone, iPad, and iPod touch - Apple Support
If you delete an app, it doesn’t cancel in-app subscriptions that you might have. While deleting an app, you might see a Cancel Subscriptions option. Learn how to cancel your subscriptions.
If you don't want to continue a subscription you need always to cancel that subscription in time, see the following Apple articles:
If you want to cancel a subscription from Apple
If you want to cancel a subscription from Apple - Apple Support
If the subscription that you want to cancel is not listed
If the subscription that you want to cancel is not listed – Apple Support (UK)
2.
I need the invoice now.
You need help and assistant from Apple directly, see -> Contact Apple for support and service
Contact Apple for support and service – Apple Support (UK)
You are not talking to Apple here, we cannot help you with that, we are also users of Apple products & services like you.