sorry, i am lost. my customer sells groceries. they want an app anyone can install on their phone, record their email, delivery address, phone, and add items they want to buy. it could be up to 1000 members of the public.
Hello @huaquichi,
Welcome to the Appsheet community!
I would definitively need more information but if they are looking to have a registration page then perhaps using google forms would suffice. The advantage is that you can later create apps that use the information gathered by that form 
Click here to learn more on what can be done with Appsheet.
I hope this helps!