Secret is a component from #202201291535 that could store environment variables or user credentials such as username and password. They should be encoded in base64. However, the built-in security mechanism is not enabled by default.
See 202202181248#
To mount a 202201311643 or 202201311645, use the option configMap or secret inside volumes. Specify its name using name or secretName.
ConfigMap is a component from #202201291535 that contain the external configuration for the containarised application in a #202201311630. User credentials such as username and password could be store in this component but a better way to do this is to store them at 202201311645#.