The Order Form page offers a section of advanced features where you can adjust the order form.
From this section, you can control the exact number of characters to allow in the shipping and billing information fields when you click on the "Field Length Limits" link. After making changes to this section, you can click on the "Done" button to save them.
You can also affect what the "Order" button does on the shopping cart page. You have the option to set it to Does Nothing or Increments Quantity.