Follow the below procedure step by step to make your Shopify website live:
1. Log in to your Shopify admin
Add the new domain in Shopify
In Shopify, go to Sales Channels > Domains > Connect the existing domain and then paste in the domain you want to connect.
2. Log in to your domain registrar and Update DNS records
Make the following changes to the DNS records: Replace the @ or main A record with the following IP address: 220.127.116.11
Add or replace the www CNAME with storename.myshopify.com (i.e. your store Shopify link without the HTTP bit, which you can find on the domains settings page)
3. Before go-live remove any storefront passwords
In Shopify, go to Sales Channels > Preferences > Password protection > untick enable password.
Otherwise, no one will be able to access your site even once it's live.
4. Set as the primary domain if it is relevant
Whilst in Sales Channels > Domains, you can set your primary domain.
Ensure that you also check the 'Redirect all traffic to this domain'. This means that traffic to all other domains will be directed to your primary domain. This is crucial for good SEO.
5. Adding other domains
You can repeat steps 1 and 2 with other domain names you own. All domain names will redirect to the 'primary' domain, which you can change at any time with the 'Set as a primary option next to each domain name.