The Proper Stance Width
The correct stance width is different from person to person.
It really depends on their body type and golf swing.
Some golfers do very well with wide stance. Others prefer narrow stance width. Either one is fine as long as you are hitting the ball well.
But there are basic rules to the stance width.
The stance width varies with a club because of the centrifugal force. For driver, you get more centrifugal force from the swing so you need wider stance to support your swinging motion.
But with short iron, you don't need wider stance because you get less centrifugal force.
Too Wide vs. Too Narrow
If your stance width is too wide, it restricts your turn and the weight shift to the right foot. If you stance is too narrow, you lose your balance during the golf swing.
So you have to find the proper stance width that gives you enough balance and allows you to turn and shift your weight correctly.
Driver to Wedge
As a basic rule, your stance width for driver should be about shoulder width.
Outside of your shoulders should be even with inside of your feet (heel) for your driver.
Tiger Woods uses the same philosophy for stance width.
With a middle iron, your stance width gets narrower. Your heels are in line with your armpits.
With your wedge, stance gets even narrower than that. The outside of your shoulders are in line with outside of your heels.
Some people have slightly wider stance or narrower stance than this. But that's fine as long as it lets you turn fully and shift your weight to the right.
Now you know the basic rule, you should experiment with the width to find what works best for you.
Lots of long hitters have wider stance. So amateur golfs think wider stance is better for more distance.
But this isn't true for most people. Those long hitter on tour are very flexible so that they can turn fully with wider stance.
But if you are not so flexible, you might want to use narrower stance to turn more to the right. This might give you more distance.