There are several diseases that can result from having misaligned feet. For example: bunions, hammertoes, heel spurs, ancle pain, ingrown nails etc.
The proper alignment of your feet is by having your feet parallel with each other, and toes straight.
The most common form of misalignment is an external rotation of the feet, having your feet spread open like a fan and an internal rotation of the ancle, toes curling externally.
It is possible to have internally rotated feet. But it is more rare.
You can simply diagnose yourself by standing barefoot, and look down at your feet.
The reason why your feet are not properly align is because, the rest of your body is misaligned. Treating the feet directly through exercises or other remedies is generally going to be unsuccessful.
If we are talking about externally rotated feet, it is almost certain to also have a forward tilted pelvis, and if you have a forward tilted pelvis you also have an overarched low back, forward rounded shoulders and a reverse curve in the neck.
The reversed curve in the neck moves weight forward in front of your feet, changing the center of gravity. So in order to compensate and maintain the balance of the body you arch your back and tilt your pelvis forward in order to move the weight of your head back and maintain equilibrium.
Which means that your feet problems are caused by your neck, and the only way to realign the feet is by restoring the normal curve in your neck.
This makes the process rather counterintuitive, because you have to stretch your neck in order to realign your feet.
The reason why most people have a reversed curve in the neck is because they sit for up to thirteen hours everyday, which makes the muscles in the back of your neck very tight.
Which is also why externally rotated feet are more common than internally rotated feet. Is the weight moving forward in the upper side of your body that tilts your pelvis forward and your feet externally.