Does billing happen automatically?

By default, an automatic renewal for the subscription is enabled. You can disable it through your account any time.

Login to your account.

Click on your profile at the left side and select "Account".

Go to the "Subscription" tab and click "Cancel Subscription".

Follow a few steps to complete the cancellation.

Your subscription will stay valid till the end of the billing cycle and then expire if you don't renew it manually.