Populate Order Notes

I created a textarea on the Order Form, but instead of it populating a Contact’s Custom Field, I want it fill in the Order Notes (Order0JobNotes) or Order Item Notes (OrderItem0Notes) for the particular order.

Here is the code for the textarea in the Shopping Cart:

<div class="infusion-field">
    <label for="inf_custom_AdditionalAttendeesInformation">Additional Attendees Information</label>
    <textarea cols="24" id="inf_custom_AdditionalAttendeesInformation" name="inf_custom_AdditionalAttendeesInformation" placeholder="Additional Attendees Information" rows="5"></textarea></div>

Any suggestions