WooCommerce: replace default shipping option title

functions.php

<?php
// Paste everything below this line to your child-theme's functions.php file.

// Renames any shipping option titled exactly 'Weight Based Shipping' to 'Shipping'.
add_filter('woocommerce_shipping_method_add_rate_args', function($rateArgs) {
    if (isset($rateArgs['label']) && $rateArgs['label'] === 'Weight Based Shipping') {
        $rateArgs['label'] = 'Shipping';
    }
    return $rateArgs;
});