Almost all web hosting company have affiliated program. If you are already an customer of any web hosting company, you should be able to activate your affiliate program from client area.
If you are not an customer of any web hosting company but want to join its affiliated program, contact the hosting company for signup url.

An affiliate program is a marketing program where you receive a commission for helping the parent company generate sales. When your any friend, client or your website, blog visitor come to our site by clicking your referral link or ads, the transaction is tracked. If this transaction results in a sale, you get paid for [...]