http://iscoresports.com/

What does the Copy Roster option actually do? I was trying to copy a roster from one game to another without having to retype everything manually.

Do you mean the 'Copy Lineup to Roster' button in the Starting lineup Options in a game? If so, then that copies all of the players, their numbers and positions you entered from the starting lineup and copies them to the team roster. Once on the team roster, you can then use that team in another game without having to retype everything. Note that existing players on the roster who aren't in the game lineup will not be deleted. Players in the lineup and not on the roster will be added to the team roster.