This will explain how File Sharing works from the iPad to the computer and then back the other way. You still do the file sharing in iTunes when your iPad is connected to your computer.
Obviously you must have compatible apps on your iPad and computer to even use file sharing such as Pages or Documents to Go for word processing on the iPad and Word or a comparable Word Processing program on the computer.
There other other ways to get files from the iPad to the computer - one way being to email the file to yourself. Another way would be to use a Cloud app like DropBox.