YITH WooCommerce Gift Cards is a plugin that allows creating and selling gift cards (both virtual and pre-printed ones) in your e-commerce store and that users can redeem when purchasing your products.
The integration with YITH Subscription allows using a gift card to purchase a subscription product and the next renewals will use the remaining balance until it ends and if the gift card has not expired.
After installing and activating the plugin, you can start creating your gift cards by following this documentation.
When users will purchase a subscription-based product on your store, they will have the possibility to use the gift card code as shown in the image below.
If there is a remaining balance, this will be automatically used on the next renewals until the available amount ends or the gift card expires.