I've seen many apps do this. Lux comes to mind, also the music player app, and other apps. They display a notification on the lockscreen that has functionality you can interact with. I read lockscreen widgets have been removed on 5.0+, but I still see these apps creating these lockscreen functionality.
I am new to Android development so maybe I am confused on the terminology. Where can I find info on how to create this type of lockscreen functionality.