Access to an AWS service
Many AWS services require that you use roles to control what that service can access. A role that a service assumes to perform actions on your behalf is called a service role. When a role serves a specialized purpose for a service, it can be categorized as a service-linked role. See the AWS documentation for each service to see if it uses roles and to learn how to assign a role for the service to use.
For details about creating a role to delegate access to a service offered by AWS, see Create a role to delegate permissions to an AWS service.