Domain registration service you can reference

• Namecheap[https://www.namecheap.com/]
• GoDaddy[https://www.godaddy.com/]
• Google Domains[https://domains.google/]
• Bluehost[https://www.bluehost.com/]
• HostGator[https://www.hostgator.com/]
• SiteGround[https://www.siteground.com/]

after buy domain, you need to configure the domain in shipstore

• go to shipstore admin-dashboard
• click on the domain configuration
• input your domain
• click on the save button
• you can see the domain in the domain list
• you can click on the domain to configure the domain