The default tags in AWS are basically cost allocation tags. They can be activated in the billing section, which we will explain in a minute. Cost allocation tags are special tags that are used by Cost Explorer and other services for allocation and visualization. So they can be explicitly used and displayed in the various views of various services. So take a look at the screenshot. Here we can see the Cost allocation tags section in AWS Billing. We can tell that CostCenter and Name are active and enabled as cost allocation tags, while the others are inactive. These inactive tags were once set for resources that are not in use any longer.

Once the cost allocation tags are activated, the console detects all tag keys used and suggests those for activation as cost allocation tags as well. Otherwise, they won't show up in Cost Explorer charts. The term User Defined means that a user created these tags and that they are therefore custom tags. AWS generated tags were automatically generated, such as createdBy, the createdBy Amazon WorkSpaces Tag. These were created and applied to support AWS resources for the purpose of cost allocation. They can only be view in the AWS Billing and Cost Management console and reports. They do not appear anywhere else in the AWS console, including the AWS Tag Editor.

Also, note that in this Cost allocation tags section, all the tag keys that are and were used in the account will be shown here. However, if you don't enable the Cost Allocation Tags option, you will not be able to evaluate certain views in the Cost Explorer and other services. For example, if I want to know what costs have been incurred for all resources with a specific cost allocation tag, then I won't be able to select or see them.

To prevent you from failing to find your resources with those cost allocation tags, I will show you how to enable this option. Let's see how you can enable AWS generated Cost allocation tags. First, you need to log in to your Master account as an IAM user with the required permissions. Next, type Billing into the search field and go to the Billing console. Select Cost Allocation Tags on the left side menu. And then, simply click on Activate to enable the tags.