AniDB

wat is it for anyways? is it for saying that ur sharing the file or is it for a record of what anime u have watched. and i dont get wat the different things are when you go and add a episode that u have watched to ur list

MyList is mostly to keep track of what you have. It`s a sort of personal database which could replace your old Excel-file to keep track of what you have
I`m using it to indicate what I have and what I have seen. Of course you can do much more with it, but these are the functions where it was built for.

u mean what i have to share or bought?

and am i allowed to use it as wat anime i have seen?

I don`t care what you share or what you`ve bought actually. Neither does AniDB
MyList is, as I said before, just a list of what you have (or have seen). You can use it for either way, that`s up to you how you want to use it. But since currently you have to click the specific files to add to your MyList, it`s mostly fansubs/dvdrips that you can add to your MyList. After that, you can select whether you have them in share, on CD, on HD, or whatever.