How do I cancel a subscription bought on the website?

Open the billing page on the website and cancel there. You choose between keeping access to the end of the period you have paid for, which is the usual choice, or cancelling immediately. You will not see this option if you bought through the App Store; those are cancelled in Apple ID settings. After cancelling, your account returns to the Free plan and none of your data is deleted.

Cancelling a subscription bought on the web

Where

From the billing page. The option appears for anyone with an active paid subscription. It does not appear on the Free plan or for lifetime purchases, since neither has anything renewing to cancel.

Screenshot to be added

The billing page with the cancel subscription option

The two choices

Until the end of the period: you keep your features until what you paid for runs out, and it does not renew. This is what most people want: you paid for the month, so use it.
Cancel immediately: the subscription stops at once.

If you cannot see the option

Then you most likely bought through the App Store. Store subscriptions do not appear here and cannot be cancelled here; they are cancelled in Apple ID settings on your device.

If cancelling fails

The payment provider can refuse the request for a technical reason. When that happens we tell you the cancellation did not go through rather than saying it did: believing a subscription is cancelled while it renews month after month is far worse than an error message.

After cancelling

Your account returns to the Free plan. Your data is not deleted. Projects, scripts and ideas all remain, and what stops is the features that need a paid plan.