Within your Shopify account, you can create a type of discount that allows you to offer free shipping to orders. Shopify allows you to configure this discount only for subscriptions.

1. Go to Discounts in the left sidebar in your account
2. Click on Create Discount and select the Free Shipping option

1. Select Automatic Discount

1. Apply a title - we recommend something like free shipping for subscriptions -
2. In Purchase Type select Subscriptions

1. Scroll down to Recurring payments for subscriptions and select Discount applies to all recurring payments

1. Finish configuring the rest of information as you'd like and click on Save

Now only the products that have a subscription will have free shipping for all recurring payments and orders.