Dear kyle518,

Yes, the optional essay is one place where you can submit a brief paragraph on how you plan to prepare for business school. Some applications will also ask for any specific coursework you plan to take in preparation, or might offer an "additional information" section where you can submit a brief paragraph on your plans. If none of these options present themselves, then your other alternative is to email the admissions office. In your email, you would basically state you wanted to make them aware of your plans, but did not see an appropriate section of the application to include the information.

Good luck,
Lisa