for using CreateFile()

i am using c++ to wite the createfil() function, what header file should i include??

It is, (albeit indirectly), included within windows.h.

i.e.....i just type #include <windows.h>

and i can use this?
how about other kind like handle, dim...?

Including windows.h adds most of the things you need for basic Win32 programming. There are some things that are more specialised that you need to include seperately, but for beginners, it is good enough.

The answer to your question is, therefore, yes.