It will depend on where you started the free trial. If you started the free trial iwith an in-app purchase, then it is managed by Apple and easily cancelled.
If you want to cancel a subscription from Apple - Apple Support
What is more likely is that you arrived on their website first, which is common when using a link from a Social media site or Website advertisement. In this case you have to cancel the subscription with the developer, because that has bypassed Apple's ability to manage the subscription. The Hint website does provide this information for cancelling:
https://help.hint.app/hc/hint-help-center/articles/1722517688-how-do-i-cancel-my-subscription
More questions about their subscriptions are available here:
https://help.hint.app/hc/hint-help-center/en/categories/subscription-and-billing
Their help seems to be limited to their Chatbot:
https://help.hint.app/hc/hint-help-center/articles/1722517846-get-help-from-hint-support