vitamin d

I have a problem with dry skin and it gets flaky sometimes and also very itchy a friend of mine recommended I start supplementing with vitamin D do you know anything about this type of condition and if the supplementation can help?

I heard that vitamin D is an awesome thing to supplement with because it's good for your joints and Health. And that you're supposed to if you live in a cold climate get vitamin D supplement it because you're not getting enough of it from the Sun. My question is how do I take it if I supplement it