Customers are able to manage their subscriptions via the Customer Portal. Customers will either be able to access their unique hashed links via the email notifications or log
You can also set this up in your notifications to provide links to your customers to manage their subscriptions. Of course, you are also able to manage the details for your customers as well, in case they contact you directly.
Context for a customer account and portal inclusion:
When an order is placed, we create a customer within your Shopify system, as long as one doesn't already exist (if it does, the link automatically integrates with the existing account). The unique identifier for each customer is their email address. Subscriptions will be associated with the email provided with the initial subscription order.
NOTE: When a subscription order is made, that does not automatically create a Shopify customer account for them, as there is no password provided. If they provide a password in the checkout account form, it will create the account when the order is completed. If this customer were then to register an account with the same email address, their previous order will be automatically connected and they will be able to manage their subscriptions.
If a customer were to register with a different email and try to go to their manage subscriptions link on the store's page, they'll receive the following notice.
Click here for more information on account creation upon checkout.