AWS CloudFormation is the infrastructure-as-code service of Amazon Web Services (AWS). In a template you describe which AWS resources you need, such as EC2 instances or RDS databases, and CloudFormation provisions and configures them as a stack. This lets you set up the same infrastructure repeatably across multiple regions and accounts, track changes through version control and delete a stack again. The service is available through the console, the API, the AWS CLI and SDKs, and it manages AWS resources only. It is a cloud service with no self-hosted edition and is not open source.
AWS is a subsidiary of Amazon, which is based in the United States, so US legislation such as the CLOUD Act can apply. Customers decide in which AWS Region their data is stored, and AWS offers a Data Processing Addendum with Standard Contractual Clauses for transfers to third countries. Because templates are specific to AWS resources, using CloudFormation increases dependence on AWS; organisations that value portability and independence from US providers can look at vendor-neutral tooling for infrastructure management.