Currently, the Facebook Pay system is available for users on its main platform, as well as on WhatsApp and Instagram.
"Starting this August, businesses in the US who use participating platforms will have the ability to enable Facebook Pay as a payment option directly on their websites, giving their customers the ability to speed through checkout without having to re-enter their payment information," the company said in a statement on Thursday.
"We're starting the rollout with Shopify merchants and expect to expand availability with more platforms and payment service providers over time," the social network added.
People already use Facebook Pay to send money, shop, donate and more, across Facebook apps and services.
The company said that Facebook Pay is designed to help businesses drive conversion higher by giving customers a low-friction and mobile-friendly way to pay online.
"Payment details are encrypted and securely stored, eliminating the need for businesses to manage customers' card or bank account numbers," it added.
"The card and bank account numbers that people provide will not be used to personalise their experience or inform the ads they see".
Shopify in February partnered with Facebook to bring its checkout and payment processing system -- Shop Pay -- to Facebook and Instagram.
Facebook last month rolled out the ability for Messenger users in the US to leverage QR codes and payment links when they want to send or request money with Facebook Pay, even if they're not connected on Facebook.