File static class
File
static class can be easily used for this purpose.
File.Copy(@"sourcePath\abc.txt", @"destinationPath\abc.txt");
File.Copy(@"sourcePath\abc.txt", @"destinationPath\xyz.txt");
Remark: By this method, file is copied, meaning that it will be read from the source and then written to the destination path. This is a resource consuming process, it would take relative time to the file size, and can cause your program to freeze if you don't utilize threads.