Adding the Express Checkout Button
You must show a Clearpay checkout button on your cart and/or product pages to enable Express Checkout. When clicked, the Clearpay checkout button will start the checkout process in a popup flow (the redirect flow can optionally be used with Deferred Shipping).
How To: Set up PayPal Express Checkout in CS-Cart — CS-Cart 4.17.x documentation
Handle Paypal Express Checkout PHP
Episode 49 - Express Checkout in Your Shopify Store - JadePuma
Adding PayPal Payment Buttons to Your WordPress Sidebar Easily - Tips and Tricks HQ
Express Checkout - FunnelKit
PayPal Express Checkout in PHP for Single Product
Handle Paypal Express Checkout PHP
WooCommerce Buy Now Settings - StoreApps
Payment Button Not Showing in the Shopping Cart - Community resources - Forum
Get Checkout
Adding PayPal Express button on any WooCommerce Custom Page - WebToffee
WCS Hub - Tips and Tricks for Websphere Commerce: April 2012
wordpress - How to add express checkout button (Google Pay / Apple Pay), on my product card located in my homepage - Stack Overflow