The Affiliate Program is a way to cooperate with great companies and get a profit for it. You choose one or several companies in which service you are sure, promote their products and receive the reward for your work.
I can show you on an example of Unihost Affiliate Program. To become the partner you should pass 4 steps.
1. Register here for free: Unihost Affiliate Program
2. Receive a referral link or a banner after the registration.
3. Place it on any kind of a platform (website, blog, social media account, forum etc.).
4. Receive up to 25% commissions from the sales of your referrals (those who opened your link and purchased something on our website).
So all you have to do is to place the link or the banner on your platform or just send it directly to those who can be interested in Unihost service and products and earn money on your recommendations.