Affiliate Marketing without a website is one of the reasons people become affiliate marketers. When you join an affiliate program they will give you marketing materials.
If you are going to be selling a product the affiliate merchant will give you a website to promote. You do not need to do anything to that website because it is already set up for you to get credit for all of the sales.
Some affiliate marketers prefer to get leads for advertisers. You can join a cost per action affiliate network and promote landing pages that are provided by the affiliate merchant.
This is a popular way to do affiliate marketing without a website because you’re not actually selling anything. All you do is get people to fill out lead forms and you eanr money.
One final way to do affiliate marketing without a website is to start a blog for free at Blogger.com. You can then monetize it with Google Adsense ads and make money when people click on the ads.