If you decide that you would only like to offer subscriptions to a specific product and disable one-time purchases, you can do so from that product’s page.
Go to “Products” in the left Shopify navigation and select or create the product you would like to offer as subscription only. Scroll down to the subscription section, and select or create a subscription plan if one is not already applied.
Once the subscription plan is applied, you will see a checkbox that says “Only allow purchase of this product as a subscription.”
Once you’ve added a plan to the product, you can view it, edit it, or remove it from the same section:
Once you’ve selected this option, you will no longer see the option for one-time purchase on your product.
Warning: Do not do this step until you’ve installed the theme code and launched subscriptions, otherwise you will disable all purchase options for the product.