Add to cart a hidden product

Hello everyone,
I would like to program a button "to add to cart a hidden product in the shop.
How can I proceed?
I want to do this because I need to be able to change the price based on parameters entered by the customer in a form.
Thanks for your help

https://www.wix.com/velo/reference/wix-stores/cart/addproducts

Merci , j’ai regardé le lien, ça me convient parfaitement
Thank you, I looked at the link, it suits me perfectly