There are basically 3 things to generate income through websites:
1. SEO
2.Website content
3.ADs
SEO, is search engine optimisation. Which means, the website is optimised as such to be visible on top by search engines. This process will make your customers know your website.
Website content: Website content is important to retain your customers. If your customers find your website useful they will come again.
ADs: This is the source of income. How your ADs are placed on the website will decide the number of clicks and give you money.