The "paper" you are referring to is likely the SpongeBob gives Mrs. Puff at the beginning of the episode. The Episode Context
This note ironically serves as the evidence that lands Mrs. Puff in jail once again, as she had destroyed it earlier, and its "reappearance" leads to her being arrested for littering. [S7E28] summer job
"Dear Mrs. Puff, I'm sorry for crashing your boat into the Krusty Krab. Your student, SpongeBob." The "paper" you are referring to is likely
: Mrs. Puff attempts to flee from SpongeBob, but her boat crashes through the front of the Krusty Krab. as she had destroyed it earlier
If you are thinking of a different show or specific scene involving a summer job and a paper:
Is this a reference to a different series like ?