AWS CloudFormation is used for deploying AWS resources.
In CloudFormation, we have to first create a template for a resource. A template is a simple text file that contains information about a stack on AWS. A stack is a collection of AWS resourced that we want to deploy together in an AWS as a group.
Once the template is ready and submitted to AWS, CloudFormation will create all the resources in the template. This helps in automation of building new environments in AWS.