Where did I subscribe?

Open Profile › My Profile › Subscription and look under your plan:

• “Subscribed on the web” or “Subscribed on copeel.com”: you subscribed on copeel.com. You manage it from your account on the website, and we handle refunds.
• “This access was given to you for free.”: you pay nothing, and there’s nothing to manage.
• None of these: you subscribed in the app, with your Apple Account. You manage it with Manage Subscription, or in iPhone Settings › your name › Subscriptions, and Apple handles refunds.

See also Cancel your subscription and How do I get a refund?.