I ask for your name so that when I reply back in regards to your contact request, I can formally address you.
Your email address is required so that I can send you a reply back in regards to your contact request.
By providing a subject to the contact request, it'll make it easier to distinguish the unique request from others.
By providing a project type like 'Web Development' it will make it easier for me to understand your needs.
Providing a budget helps me understand your project's scope.
