Kubernetes provides a built-in resource type called Secret to manage sensitive data, which can be fed into containers as environment variables or mounted as volumes. However, this default solution has limitations, such as exposing secrets when stored in version control and requiring complex key management systems for encryption. Alternative solutions like Hashicorp Vault and Infisical offer more robust secrets management capabilities, including auto-reload of deployments upon secret changes, making it easier to manage sensitive data in Kubernetes clusters.