Saving game in play mode?

hello i am making a free roam adventure game and i was wondering if there was a way to save the players current progress when playing, such as having a save button in game. I also wonder if there is a method of saving the game so that after you exit the game and open it again, that your saved game from last time would still exist?

if you could help me with this i would be very thankful

Either read:

or have the player data uploaded to your web server using the WWW/WWWForm class.