If you want to change the text of WooCommerce notices

change-woocommerce-notices.php

<!-- You can add this near the bottom of your footer.php -->

<!-- As an example, assume your checkout page had these 2 notifications by default -->
<!-- and you wanted to replace both of them: https://i.snipboard.io/MvmKWL.jpg -->

<?php if($post->ID == 353034) } /* Change this ID to match the ID of your checkout page */ ?> 
<script>
    var getAllWooMessages = document.getElementsByClassName("woocommerce-info");
    for (var i = 0; i < getAllWooMessages.length; i++) {
        (function(x) {
            var theinnerhtml = getAllWooMessages[x].innerHTML;
            //console.log(theinnerhtml); // optional, if you want to check what the text is inside each notification

            // Below here, you will enter in the text of the original WooCommerce notifications, one at a time
            // You do not need to put in the entire text, for example, in #1 below, "Coupon added but not yet applied" would be enough to work
            // Add as many of these as you need, but keep renaming the variables 'substring_3', 'substring_4', etc., as you add more

            var substring_1 = "Coupon added but not yet applied:<br>Sorry, this coupon is not applicable to selected products.";
            var substring_2 = "Your cart is currently empty.";

            // In the code blocks below, as you copy them, replace 'substring_1', etc., so they match the variables you create above

            if (theinnerhtml.includes(substring_1)) {

                // Below here, between the double quotes, add in whatever text you want to replace the original message with (overwrite my example)
                // Do the same for all of the code blocks below, including any you might make yourself

                getAllWooMessages[x].innerHTML = "Your free gifts will be added once you add your shoes to your cart. Please select your shoes above to receive your $558.94 worth of free gifts!";
            }

            if (theinnerhtml.includes(substring_2)) {
                getAllWooMessages[x].innerHTML = "Your shopping cart is empty. Please add products to your cart to continue.";
            }

        }(i))
    }
</script>
<?php } ?>