X-Cart Paypal integration supports the Pay in 4 payment option called "Buy Now Pay Later" in X-Cart. A store admin can enable the "Buy Now Pay Later" payment option in the store's Admin area. However, it will display only for locations approved by PayPal in the storefront. So, before enabling this payment option, contact your PayPal assistant for consultancy.
On the X-Cart side, when a customer uses the "Pay Later" payment option, the payment will be accepted as a regular one. All delayed payments are a matter of the interrelations between the store customers and PayPal.
To configure the Buy Now Pay Later payment option:
First, enable PayPal Checkout Payment as described here.
On the PayPal Checkout settings page, enable the "Display the 'Buy Now with PayPal' button" toggle.
Click the Save changes button.
That's it! The Pay Later payment option should become available to the customers in the storefront.
In the storefront, the Pay Later payment option displays:
on the product details page, included in the PayPal Credit button;
in the cart preview widget;
on the cart page;