After your account is verified by Facebook, a Shop section will appear on your Facebook Page. This is where your products and collections are displayed when they are available to Facebook Shop. You can manage your products, orders, and customers in your Shopify admin.
Facebook adds a Shop Now button on your main Facebook Page which links to the Shop section on your Facebook Page. You can make changes to the button on Facebook, including by linking it to a Shopify online store.
Customers can message you through your Facebook Page by using Messenger, and you can respond as your business. If you add the Messenger channel, then customers can buy your products directly in chat by using an automated system.
Your customers can also contact you by email by using the Contact Seller button in their receipt and in their Purchase History in Facebook. This button will forward customer inquiries to the customer support email that you have on file with Shopify.
Facebook requires that you handle the customer information that you gather through Facebook Shop according to their Commerce merchant agreement.
When a customer selects a product to buy from your Facebook Page, they are taken to the Shopify checkout to enter their payment information. Customers on Facebook can only buy one product at a time, because they are automatically redirected from Facebook to check out on Shopify. They automatically receive confirmation emails about their orders from your store, and their orders appear on the Orders page in Shopify.