Change Product name into Service

If you want to change the word “Product” throughout your site, you can use this plugin:
https://wordpress.org/plugins/say-what/

If you want to change it in this place only, you’ll need to make a custom template.

Make a child theme.

Copy
wp-content/plugins/woocommerce/templates/cart/cart.php
to
wp-contents/themes/your-child-theme-name/woocommerce/cart/cart.php
and alter the table heading label in the copy.

You can also remove the quantity column in this custom template.

PHP skills would be required.