A Microsoft offering that enables tracking of cloud usage and expenditures for Azure and other cloud providers.
@Michael Brunak , thank you for reaching out to Microsoft Q&A for this question.
Note that - not all resources in Azure support tags. Some of these resources are created as part of other resource creation/update operation. For details, please see Tag support for Azure resources.
Also, to understand tag usage in Cost Management & Billing, please see - How tags are used in cost and usage data
Please let me know if you have any questions.