The AWS console allows the user to create and update cloud infrastructure resources in a user-friendly manner. Despite all the advantages that such a high-level tool might have, using it is repetitive and error-prone. For example, each time we create a Lambda function using the AWS console, we need to repeat the same operations again and again, and, even if these operations are intuitive and easy as graphical widget manipulations, the whole process is time-consuming and laborious. This working mode is convenient for rapid prototyping, but as soon as we have to work on a real project with a relatively large scope and duration, it doesn't meet the team's goals and wishes anymore. In such a case, the preferred solution is IaC (Infrastructure as Code).
IaC essentially consists of using a declarative notation in order to specify infrastructure resources. In the case of AWS, this notation expressed as a formalism based on a JSON or YAML syntax is captured in configuration files and submitted to the CloudFormation IaC utility.