Registering a domain name involves a commitment from a Domain Name Registrar for a minimum of 12 months.

Tools like Terraform and AWS CloudFormation are used to create, update and delete infrastructure such as networks, EC2 instances and database.

While AWS does offer the ability to register domain names (which is done through gandi.net), this is not something you would do with tools like Terraform because you cannot simply "unregister" a domain name.

You could choose to use such tools to add sub-domains to an existing domain. They just aren't appropriate for the initial purchase of a domain name.