Every golf shot needs two things. First muscular strength to hold the foundation of the swing. The swing motion for the drive, irons, chip, bunker and putting shot.
The second thing is mobility in your joints and especially the thorax possibility to rotate around its spine.
Check your torso rotation by sitting on a chair with a straight back as possible.
Cross your arms over your chest. Left hand touches your right shoulder and vice versa.
Try to rotate your torso to your right without moving head or knees (the knees and head points forward). Then you try to do it to the left. This is the same rotation the golfswing includes!
The drill for checking your shoulder turn without moving your legs or hips. Also a good drill for checking your ability to separate your upper and lower body.
If can do this rotation with 20-45degrees both ways you are good-perfect. If the score is zero you got to increase this motion range by rotation specific exercises to be able to be a better golfer.
Next part will concern setup to the ball. Good luck!