The full answer is that you could code it by hand or use a plugin. 🙂
Many form plugins, however, generate loads of HTML and CSS already, and due to the fact that styling forms is a huge pain (even for a CSS geek like me), you’d be writing tons of CSS overrides to overcome the aggressive coding of, say, Gravity Forms or the like. I spent a huge amount of time re-styling a Gravity Form, and probably used some foul language while doing so (that was just CSS, not HTML changes).
If I were doing this, I’d use Contact Form 7, which allows you to stick all your HTML in its admin screen for each form. You would have to learn the way to define fields in Contact Form 7, which is not hard IMO – it’s way easier than raw PHP. Take a peek here and see if it looks easy or hard. And you’d still need some add’l CSS to work with Contact Form 7’s CSS, but maybe not too bad.
Then again, someone may chime in with an easy way to hand-code the whole thing. Not my cup of tea, though. 🙂
Cheers, Dave