Hextom: Free Shipping Bar

Easy to setup. You can change the colors and text to be whatever you like.
Just pick your hex codes and google font and you're done.

You still need to create a free shipping rate on in your store. Instructions are here - https://help.shopify.com/en/manual/shipping/setting-up-and-managing-your-shipping/setting-up-shipping-rates#create-free-shipping-rates