We're now going to show you how to set up CloudTrail in your AWS account. Once CloudTrail has been enabled, it will start to record all of the API calls made in your account to the AWS service and then deliver them to you as log files in an S3 bucket.
When we talk about API calls we mean things like:

• Actions performed in the AWS console.
• Calls made to AWS APIs using the CLI or SDKs.
• Calls made on your behalf by AWS services. Think CloudFormation or the auto scaling service.

Each entry in the log will contain useful information, such as:

• The service that was called
• The action that was requested
• The parameters sent with the request
• The response that was returned by AWS
• The identity of the caller (including IP address)
• The date and time of the request