To learn more about Shopify, you can read this article: What Is Shopify? How Does Shopify Work Exactly?.
Hope it helps!
Eunice here from Shopify, thanks for posting, and a very warm welcome to the Community!
Shopify offers free webinar sessions which you can find here. I recommend attending the Getting Started with Shopify Webinar to learn more about the process of building your own online store and making your first sale.
Another handy resource is this awesome blog which covers what Shopify is and how it works.
If you have any further questions about Shopify I'd love to help. Cheers!