Who develops a store on Shopify?

I am planning to create and launch an online store in the near future. I have heard that Shopify is a great platform to create your own online store. You can even create a store yourself without any special programming or web design skills. However, in order for the store to be fully optimised and, as a result, produce a high conversion rate, I think it’s best to leave the development to professionals in this business. Can you tell me who develops a store on the Shopify platform?