The subscription is managed by Apple. You can view subscriptions following the below steps:
- Open the Settings app.
- Tap your name.
- Tap Subscriptions. (If you don't see "Subscriptions" tap "iTunes & App Store" instead. Then tap your Apple ID, tap View Apple ID, sign in, scroll down to Subscriptions, and tap Subscriptions.)
- Tap the DrawingApp - subscription that you want to manage.
- It will display all information about available subscription plans and active subscription plan (if any) for DrawingApp.
Alternatively, you can tap here to open the app to learn more.