You distribute your referral (partner) link by some convenient method. This can be simply a small post on a social network, a video, an article in a blog or a brief review that will contain your link to the site with a unique identifier. The possibilities are limited only by your creativity. 

When someone follows this link and creates an account, that user becomes your referral and you receive 10% of each payment he makes to his service account. You can use this money to pay for the service or simply withdraw it.