Go to Billing → Billing methods.
Here you can add a primary billing method for your account. This is the default we'll use to charge you for future transactions, and for your stores.
Here's how to set different billing methods for your stores:
- Click “Add new billing method”
- Select your store in the dropdown
- Select the billing method you want to use.
To read about setting up a primary billing method for your whole store, go here.