The Shopify platform allows developers to build custom online stores using their own design and functionality. Create a Shopify developer account: Sign up for a free account at shopify.com/developers. Familiarize yourself with the Shopify platform learn about. Shopify's architecture and how it handles data, pricing, and checkout. Shopify's online development environment, or set up your own local development environment using tools like the Shopify Theme Kit. Shopify's Liquid template language to create custom pages and templates, and use the Shopify API to add custom functionality to your store. Test your store on a development store and then deploy it to a live store. 

Shopify Plus is also available for enterprise level businesses, which provides additional features and functionalities.