Google AdSense is a free, simple way for website publishers of all sizes to earn money by 
displaying targeted Google ads on their websites. AdSense also lets you provide Google search to your site users, while earning money by displaying Google ads on the search results pages.
How does it work?
Choose the type and placement of ad units to be displayed
Specify where you want ads to appear
Choose what types of ads can compete for those slots
Highest-paying ads display
Advertisers bid on your inventory in a real-time auction
Always show the highest-paying ad
Get paid
Google bills advertisers and ad networks
Get paid through our reliable payment options
Here is a AdSense Sign Up Link
Their specialist team will review your application and you’ll receive a follow-up email within about a week. If you’re accepted into the program, you can sign in to your new account to get the HTML code that will display ads on your web pages.