Google Domains is now in public Beta and is available only to users in the United States. The rest of the world might have to wait a little longer to utilise this service. If you are eligible to use the new Google Domains integration, you should see a “Buy Now” option in Blogger’s publishing settings.
When you login to the Blogger Dashboard, and navigate to the Settings menu, you should see the option under the Publishing section
Once you click on the Buy a domain option, you should be able to quickly set your BlogSpot blog to use a custom domain name which you buy. Custom domain names on Google Domains costs somewhere near 12$ per year.
In case you haven’t yet created your blog, you can log onto Google Domains, buy a domain name and use blogger as the publishing platform.
In case you need help setting up your blog with a Custom domain from Google Domains, do let us know and we might do it for you :-). Google Domains is not yet available anywhere outside the United States. This doesn't mean that you can't use Custom Domains outside the US. There are many third party Domain Registrars where you can register a domain name of your choice. We have written couple of tutorials on how to set it up for Name.com and Go Daddy. Both are trusted and widely used domain registrars. Most of my domains were registered on Name.com and a couple of them on GoDaddy. In case you need some details on how to setup your custom URL with these domain providers, then checkout our tutorials listed below. If you would like to use an alternate domain provider and would want us to write a tutorial, do let us know and we might be able to help you out.