Redirect to Checkout After Adding Product in WooCommerce

WooCommerce has a built-in option to redirect all users to the cart page when they add a product. This option is under WooCommerce > Settings > Products > “Add to cart behaviour”.

But if you want to redirect visitors directly to the checkout page, add the following code to your active child theme (or theme) functions.php file:

function custom_add_to_cart_redirect( $url ) {
    $url = WC()->cart->get_checkout_url();
    return $url;
}
add_filter( 'woocommerce_add_to_cart_redirect', 'custom_add_to_cart_redirect' );

This code redirects users directly to the checkout page after adding a product to the WooCommerce cart. On the same topic, see the post Popup after adding to cart in WooCommerce.

For more on adding fields and modifying the WooCommerce checkout page, see WooCommerce checkout – how to change and add fields.