The difference in whether I give you an estimate or a quote is determined by how detailed your request is to me. If you answers all of the questions on the estimate form, and give me as much detail as possible, I will most likely present a bid for the job, at a specific price, and this is what I call a quote.
If your request leaves a lot of unanswered questions, or your request shows me that you don't really know what you want, then at best I will give you an estimate; a price range for the work request. I may even require more information before giving you an estimate. Therefore, it is in both of our interests that you fill out the form as completely as possible, and that you give me as much detail as possible regarding what you want done.
Alternatively, you could just call me on the phone, or we could set up a time to meet. It's often a lot easier to give an accurate quote for web design or website development when I can speak with you, having you describe to me what you want, and being able to discuss the finer details of your wants and needs.