http://www.chess.com/analysis-board-editor
That should do what you want, if I'm reading your request correctly. You can't really export but can copy the PGN out and save it yourself however you like.
Though, if you mean the mobile app when you say "app game" and not the website, then you can't.
So I can't enter the game into my phone?
With the chess.com app? I don't think so. If you browse to the website, maybe. I'm not sure how well thta would work.
If you have a smartphone, look into a database or notation app. I use SCID on the Go on Android for notating casual OTB games.
Installed SCID on the go..perfect..thanks
Where can I get a chess engine to install into SCID on the go?
How do I notate an OTB game using SCID on the go?
No idea what menu options I need to chooose.
I can't recall right off if the initial install starts with a database but I think the first step is to choose File -> New Database. After that is created it will open by default. Choose Game -> New Game to start notation. When you are done with the game, choose Game -> Save Game. In the version I have it says the feature is experimental, but it works fine.
I want to have some kind of 2 player mode, when I enter my moves into the app game, so I can then export the PGN (instead of writing it on paper)
Can the app support this?