What is the difference between COPY and MOVE_UPLOAD_FILE function in php?

Copy Makes a copy of a file. Returns TRUE if the copy succeeded otherwise return FALSE.

move_uploaded_file() function checks to ensure that the file designated by filename is a valid upload file. If the file is valid, it will be moved to the filename given by destination. If filename is not a valid upload file, then no action will occur, and move_uploaded_file() will return FALSE.