I believe どなたですか is more polite.

dare desu ka means which is it

=People=

どなた＝何方

あなた＝貴方　（彼方＝かなた）

そなた＝其方

こなた＝此方

=Directions=

どちら＝何方

あちら＝彼方

そちら＝其方

こちら＝此方

(方 can be a respectful way of saying either person or direction.)

So you can see that these words are different readings of the same kanji, except for the commonly used あなた. The 貴 kanji in あなた is an honorific title (i.e. lord) rather than a (this/that/over there) location identifier.

どなた is usually written in kana.

I wrote that and it was accepted.

I believe it can but that would depend on the context