They’re functionally the same – smoking plant material in that form factor. But I’ve noticed cigarette smokers tend to hold the cigarette facing out, in between their index and middle finger. Whereas someone smoking a joint would more typically hold it towards their palm, between their thumb and middle or index finger.
The holding it inward is just an attempt to hide it. Or at least that’s how it started. Maybe some people just learned to do it that way every time.
Anyway, I hold a joint the same as a cigarette.