There are a few different ways that you can use WooCommerce Checkout.
One way is to use the shortcode [woocommerce_checkout]. This will output the checkout form on any post or page where you place it.
Another way to use WooCommerce Checkout is to add it to your theme. You can do this by adding the following code to your theme’s functions.php file:
<?php
add_action( 'woocommerce_checkout_form', 'my_custom_checkout_form' );
function my_custom_checkout_form() {
// Output your custom checkout form here.
}?>
This will add the checkout form to any post or page that uses the default WooCommerce Checkout template. If you want to add it to a specific post or page, you can use the WooCommerce_get_template function:
<?php
woocommerce_get_template( 'checkout/form-checkout.php', array( 'checkout' => $checkout ) );
?>