Customers will be able to manage their subscriptions via their customer portal (Links Below). You can also setup in your notifications section of ReCharge ways for customers to get links to manage their subscriptions.
You are also able to manage the details for your customers as well, in case they contact you directly.
When an order is placed we create a customer within your Shopify system if one doesn't already exist. The unique identifier for each customer is their email address. Subscriptions will be associated with the email provided with the initial subscription order.