The form appears to be very large and is composed of many pieces of paper. It contains labor agreements for an employee at the Krusty Krab.
Role in episode
When Plankton is controlling Sandy's pelt, he asks SpongeBob how he makes a Krabby Patty. In response, SpongeBob informs him that he is prohibited from disclosing such manners in accordance with his current labor contract, which he subsequently shows Plankton. Plankton tries to argue that they are close friends, but SpongeBob shows him a specific section of the labor agreement that forbids the disclosure of the secret formula regardless of acquaintance status.
According to SpongeBob, section 44-929b specifically prohibits the disclosure of the secret formula to friends, even when those friends are "closer 'n two catfish in a skillet."