Gravity Forms for WordPress is one of the best form builder you can find
WordPress is a platform thats growing for every year, and with this the amount of the plugins goes the same way, when it comes to form builder, Gravity Forms is something you should look on.
But if you gonna create a form of any kind, then there are actually only ONE plugin that you should work with, and thats GravityForms from RocketGenius.
With Gravity form you can create forms in any way, with their form editor you add the different block with “drag n drop”. There are lots of blocks, and each block have its own settings, and where its needed you have lots of pre-sorted CSS classes that easily can be added to change the layout of your form.
Some things cant be done in a practical way with a normal form builder, but with Gravity forms different add-ons can you easly do polls, survey, user registration, quiz and lots of other things. Last, but very important, the documentation is fantastic and its translated to many, many language.
Gravity form can be purched in 3 licence, Personal, Business and Develops.