Billing sources are cloud accounts where billing information is made accessible to cloudtamer.io. Before you attach any accounts to projects in cloudtamer.io, you must add their billing sources.
For AWS, the billing source is the management account. Once cloudtamer.io is installed in your environment, you need to set up the billing reports in the AWS management account so they save to an S3 bucket. You'll also need permission to apply a CloudFormation template that creates a role in the AWS account to allow access to the S3 bucket as well as account creation if applicable. If cloudtamer.io will not have access to the AWS account, the cloudtamer.io team can provide a CloudFormation template that creates a Lambda function that performs the replication of the billing S3 bucket. For more information, see the AWS Management Account Setup Guide (requires login; learn more here).
For Azure, you'll need to perform a few actions to grant cloudtamer.io access to your resources in Azure, such as creating an App Registration for cloudtamer.io in your Azure tenant, before you can add your billing source. For more information about this, reference the Azure CSP Setup Guide and the Azure EA Setup Guide, which explain how to set this up.
For Google Cloud, the billing source is the billing account. You'll need to create a billing account within Google Cloud and attach it to the service account before you can add the billing source to cloudtamer.io. For more information, see the Google Cloud Setup Guide.