Now we have a custom domain name & a custom design on our website. We need to tell the world about our products/services.
For selling services, create a form on your website that a customer can opt in to (can be done with code, buildify, or a contact app in the Shopify App Store.)
For selling products, click "Products" then click "Add Product". When entering product descriptions, make the customer really understand WHY this product solves their problem. Don't use a default text. Make sure to organize your groups of products by creating a collection. For example, t-shirts, sweaters, shoes, etc. This way when you click the "shoes" collection on your store, you will only see your shoe products.
Lastly, click "Online Store" and go through the taxes & shipping settings. Consult a tax expert if you're confused on how you should collect taxes in your area. Shipping settings can be custom set by weight, price amount, etc.