This is an accepted solution.
Thank you for joining the Shopify Community and sharing your question here. I understand you want to connect a custom domain to your store to replace your myshopify.com URL. I can help you with that!
Your myshopify.com domain is created when you first make your store and is your account's unique identifier. Your store admin will always be connected to the .myshopify.com URL, but you can definitely change the customer facing domain to a domain of your choice. These alternate domains are not free though, and you will be required to purchase them on a yearly subscription basis. If the domain renewal expires in the future, you could lose access to that domain and have to use a new one.
You can buy an unused domain through your Shopify admin or through a third party domain host of your choice. If that domain is already owned or in use, you will not be able to purchase it and will need to use a different domain for your business. You can learn more about this in our Help Center by following the link below:
If you have additional questions, please reply back and I'm happy to help.