Adding a contact page to your storefront will help your customers contact you if they have any questions or need help.
Now, it's easy enough to create a basic page listing your contact information but you'll probably want to add some sort of contact form to make it easy to contact you. You can do this by embedding a web form on the page. Definitely check out that article after creating the basic contact page.
Navigate to Customization > Pages and click New Page. Title your contact page and if you know some of the content you want to include here you can type it into the text editor and once you've finished scroll down and toggle Show On Site and then you can Save.
Now we need to make the link available on your storefront.
Navigate to Customization > Navigation and click the three dot menu under you footer and Edit. Title your page Contact and under Link pick Choose Page and select Contact. That's it! Your footer link to the Contact page is now live on your storefront.
There won't be any content at this point since we'll add that via a form. Head over Adding a Form to an HTML page to see how to add a contact form.