This is the page customer see when they go to Frontend page (the page is automatically created after the app is installed, its should be in the following address /apps/product-registration, note: it will be in different address if the app proxy is changed manually - don't worry about it if it doesn't mean anything).
e.g If the shop url is: mymart.shopify.com, the registration page will be: mymart.shopify.com/apps/product-registration
By default this page will show the Product registration form, however if other forms are created it will use the same path, but different query string (Don't worry about it, you can see the frontend link for the form in the backend Form > View on Frontend)
In general the form is divided into different parts (all the fields are totally customizable in the Form's admin)
The is the introduction text that list the benefit of product registration or any information you want customer to see - by default the app generated a generic text for it, but it can be change in the App admin > Forms > Form's settings.
The fields here are totally customizable in the Form's Admin
However the following fields are default that collect product information
The product name provide autocomplete function which means customer only need to type in some keywords of the product, the app will use those keywords to search products in the shop, then presented as selections for customer.
Obviously some of the products might not be in available in shopify shop, in these case the app will simply take whatever the product name customer supplied.
Register multiple products
By default the form allow register multiple products, it allow customer to register multiple products in one go, it list all products customer entered, so there is a clear visibility of what will be register. (depend on the form setting, if its one step form, it will only allow to register one product at one time)
Collect more information about the customer e.g names, address and phone number.