How can I create a one-time purchase and subscription purchase option?

How can I create both one-time and recurring subscription purchase options in my subscription group?

By default, when a subscription group is created, the products you've add to the group will be available for both one-time purchase and subscription. If you'd like to remove the one-time purchase option, you can enable the "Only sell this product as a subscription" setting on the product page in your Shopify admin.