add a text input box to products

I need to add 2 text input boxes so the user can input text for a show and booth number. I need to do this for each product, and don’t want to use the “extra info” box on the paypal review screen, I want to add this on my actual website. I see other people have asked this but I have never found the actual code to make it happen, anyone know how?

https://www.ads-software.com/plugins/wordpress-simple-paypal-shopping-cart/