Yes, you can only change the name not the name for when people @ you, for example, My name is TastyLemon16 and my @ is @tastylemon16 (Which is highlighted in green) say if I was to change my name to bob than my name would be, bob but my @ would be @tastylemon16.
If you want to change your name than tap on the top left of your screen where it says “Howdy, Justin Scott” than click on settings than profile, it is not than than keep exploring setting and profile and you will eventually find it.