I guess you are talking about generating enquiries or leads by having a application form or enquiry form on your website through SEO...?
there are so many CPA and affiliate networks like azoogle, CJ, link share, etc. you can sign up with any one of them and promote the products of your selected merchant(s). some merchants pay per lead so you get paid if you generate a lead and some merchants pay you based on sale. lead generation is providing your affiliate merchant with a visit that can potentially turn into a customer for your merchant. a prime example of lead generation is where a visitor of your site signs up with his/her email address with your affiliate partner
The forum policy doesn't allow posting me links. However, you can just type my display name to learn the basic concept of lead generation and some proven techniques to generation. Hope it helps.