Do you have categories of products that you want to show on your website? If so, each category has its own page. Do you want to be able to fill in the order form when ready? If so, you will need an “order form” page.
Your web designer will ask you about these aspects of your website, but it is good to think about that step. As a rule, more pages of the website, more value, then choose a Website Design company that you feel comfortable and do not actually give you more pages needed. Your website is your storefront window on the World Wide Web.