During your power shot or for a full swing your stance should be wide enough to create stability but narrow enough to generate a weight transfer. I don’t recommend a stance that’s wider than shoulder width, however the longer the club the wider the stance. As the clubs get shorter, your stance should get progressively narrower. Don’t narrow your stance anymore than inside shoulder width for your short irons. If your stance gets too narrow, it can lead to off balance shots or excessive body motion because your foundation of support is no longer stable. 
I would recommend fanning your lead foot towards the target slightly, while keeping your trailing foot perpendicular to the target line. With your trailing foot square to your target, you are reducing hip turn. A limited hip turn joined with a full shoulder turn, can create coil and torque that leads to more power. By turning out your front foot, you will be helping to create a fuller finish, as it makes it easier for your hips to clear through impact.
For weight distribution, your weight should be distributed 50/50 between your feet for almost every type of shot. For a short iron you might put 5% more weight on your lead foot while swinging a longer club about 5% more on your trailing foot. If you’re a beginner it will be very difficult to distinguish that small amount of weight so just keep it 50/50 until you get more efficient at your ball striking. You may want to experiment with your stance during practice to see what kind of results you get from the different weight distributions.
Finally, your body weight should be distributed evenly between the toes and heels on the fat part of your foot. Meaning from the ball of your foot to the arch. If you start with too much weight on the heels chances are your going to shift to the toes during your swing to stay balanced. This means you can very well have some off centered hits towards the heel of the club because you compensated the weight to stay balanced. The same goes if you start with to much weight on the toes, you’ll compensate during the swing to get the weight on the heels leading to strikes off the toe of your club.
