Upload, no.
Normally, you would open a chess program of some sort, there're many commercial and free around (Chessbase's Chessbase DB, one of the programs that comes with Fritz GUI (Komodo, Houdini, Deep Fritz, etc.), ChessOK's ChessAssistant, Aquarium; or free ones like SCID, SCID vs PC, Arena, ChessX, etc.), enter the moves on the board and then save the game into an opened database, be it PGN or some other format (you always have an option to export your games to PGN file).
I have playing in 3 tournaments in the past month. I do not have a notation book so I usually use the notation papers they provide. I have noticed that I have lost a couple important games that I really wanted to go over. Is there any way to upload notation to a computer to create a pgn?