question about facebook locations?

[Iris]

okay so i realized that on facebook,you are able to see where the message was sent from,literally down to the street. i find that kinda creepy. i was just wondering,if i sent a message from my iphone,but it wasn't from the facebook app,can people see it? i sent a message that was suppose to be anonymous and i don't wan't it to come back and bite me in the a** lol. i also sent a message from my macbook..will they be able to see my exact location then? and also,how can i change it so it won't tell people where i am. is it a setting on my facebook,or my devices? thanks