I need help :( please idk what to do

I need help idk what the little narration bubble is called or how to use it, it’s not the one where you put “NARRATOR” in but the one that comes from the very top of the screen if somebody can tell me what it is and how to put it in my story that would be really nice

readerMessage < your text here >

^ try that and let me know if that’s what you were looking for !
replace < your text here > with what you want it to say in the message