When working with a Shopify expert or getting support on your store, you will get asked for your Shopify store URL. It is the URL that is given once you create your store and can not be changed, its usually made up of your business name and .myshopify.com.
For example: my-store-name.myshopify.com
This is how your store is identified internally but will still show your primary domain to your customers.
Here’s a quick overview on where to find your Store URL:
Download your Shopify Resource Guide
BONUS: Shopify Launch Checklist