There are two parts to this, the Contract Viewer and the Contract Manager.
The Contract Viewer shows all the details about a contract. If it is a pending contract, it will also give you the option of accepting or rejecting it. Accepting a contract automatically rejects all other pending contracts.
The Contract Manager shows any recent contracts you've received and if you remove the date and submit, it will show all the contracts your player has ever been offered. You also have the option to accept or reject pending contracts from this screen, or clicking on Details to go to the Contract Viewer page which has additional information.
Are contracts binding?
YES! If you sign a contract, unless the team owner somehow violates a written clause, you are at the owner's mercy. If you aren't happy with an offer, don't accept and then try to renegotiate - reject it and send a message to the owner stating what would make it work for you.
Is there a salary cap?
Players can earn up to $30M (modified by league income percent) and receive up to $3M/season in bonuses.
I am a free agent and I rejected all the NPC Team offers. How do I get more?
You have to wait 3 days and then more offers will appear. Or you can visit the Recruitment Center in the forums and try to find a human team!