Youtube Monetization Guide

Once your video is submitted and approved for monetization, YouTube will place ads inside or near the video. After you’ve associated an AdSense account with your YouTube account, you will earn revenue that is generated from the ads.

If monetization is disabled for your YouTube channel, it could be for several reasons. ... Attempting monetization of videos that don't meet our advertiser-friendly content guidelines. Violations of YouTube Partner Program policies, YouTube spam policies, AdSense Program Policies, or YouTube Terms of Service.