If anyone has purchased a bicycle from a decent shop you get fitted to the bike once they help you determine what basic frame size you need.
Adjust seat height to help optimize the angles your knees go through during a crank rotation.
Adjust seat angle to help with weight distribution for your sits bones in the pelvis.
Adjust seat position fore/aft if needed to help with the angle of your upper torso (I think?)
Bars and levers are adjusted.
They did all this for me when I bought a basic fitness/hybrid bicycle for $400.00 ! 15 minutes of tinkering and they said ride it, let us know what you feel, we can fine tune from there. When was the last time anyone offered that to you at a motorcycle dealership? Motorcycles are so much easier!
Adjust gear shift and rear brake pedal height (and rear brake light switch) for the rider with the boots he normally wears.
If the bike has clip-on bars / fixed bars, there's no adjustment other than clutch and front brake lever height to take any weird angles out of the wrists.
If the bike has conventional handlebars like ours do, the steps I outlined above to get a base line.
I used to do this for every bike I sold at the Triumph, Ducati, Aprilia, and MV Agusta dealership I worked at 20 years ago.