CreateFile() is a WinAPI macro (chooses CreateFileA or CreateFileW as appropriate) that creates a new file or opens an existing file. On success, a handle to the file is returned.
Example usage of CreateFile() https://learn.microsoft.com/en-us/windows/win32/fileio/opening-a-file-for-reading-or-writing
CreateFileA() is the ASCII version of this function. CreateFileW() is the Unicode version of this function
These functions are wrappers for the NtCreateFile function.