Add-Ons Ultimate is compatible with all major page builders like Elementor, Divi, Gutenberg / Block Editor, Visual Composer, Beaver Builder, Oxygen Builder, and many others.
Note that it automatically inserts extra fields before the ‘Add to Cart’ button on your product page and will follow your theme’s styling. There is not currently a shortcode that you can use to insert the fields.
For more information on styling add-ons, please see this article.