Add New field

Hello there,
Our client website has a Product Inquiry form which is similar to “add to cart” on e-commerce site.
This product Inquiry form allows you to add as many products onto the inquiry and once you fill the form and hit submit it will send an email with the list of products the customers has added. Now we have integrated salesforce using the Free plugin of yours and somehow the developers made the “add to cart” work but in the field it shows limited field so they have selected Middle Name as the input for products list which is wrong, I want to create a new field “Others” which will contain all the products user has added to the product inquiry list. How do i do that?
We are using contact form 7.
Thanks