A well rounded storefront is going to have a number of custom pages which is important for building trust with a customer. Have you made a purchase from a website that had only two or three pages? It helps a customer see a website as legitimate if they see more than a couple of pages, even if the customer doesn't end up clicking on them.
A few examples of pages you might want on your site:
Before you create a custom page, know that the custom page essentially lives here. A custom page won't be under the Customize section for your theme. It can't be used in the theme editor to enable blocks on. This page is essentially hidden unless you place a link to it somewhere in your theme. You can see how to setup navigation and link to custom pages here.
If you forget what the URL is or you change the title after creating it, you can click Advanced to see the URL.