WordPress at a glance
function is not described

is_checkout_pay_page() WC 1.0

Is_checkout_pay - Returns true when viewing the checkout's pay page.

No Hooks.

Return

true|false. Nothing.

Usage

is_checkout_pay_page();

Code of is_checkout_pay_page() WC 5.3.0

<?php
function is_checkout_pay_page() {
	global $wp;

	return is_checkout() && ! empty( $wp->query_vars['order-pay'] );
}