Here are the steps to cancel your current trial or subscription. I've also attached photos that demonstrate the following steps.

1. Open to the App Store, tap yourprofile picturein the top right corner (or click on this link:https://apple.co/2Th4vqI).
2. TapSubscriptions(skip this step if you clicked on the link above).
3. You’ll now see all theActiveandExpiredsubscriptions tied to your Apple ID.
4. Tap on uMake, and then scroll down and tap on "Cancel Subscription" or "Cancel Free Trial."
5. On that screen, you'll notice that below the uMake app icon, it indicates that the app "Expires [DATE]", which means your subscription is canceled and will expire on the mentioned date.

For more information, read Apple's instructions at:https://support.apple.com/HT202039