Tagging is the act of assigning metadata to the different resources in your AWS environment for a variety of purposes, such as Attribute Based Access Control (ABAC), Cloud Financial Management, and automation (such as patching for select tagged instances). Tagging can also be used to create new resource constructs for visibility or control (such as grouping together resources that make up a micro-service, application, or workload). Tagging is fundamental to providing enterprise-level visibility and control.
https://aws.amazon.com/solutions/guidance/tagging-on-aws/?did=sl_card&trk=sl_card
