If you're a creator with a high volume of videos currently not set to earn ad revenue, it may be easier to bulk monetize them. Follow these instructions to turn on ads for videos you’ve already uploaded:
- Go to your YouTube Studio.
- In the column to the left, click on 'Videos'
- Select the grey box on the left of each video you'd like to monetize
- Click the 'Edit' dropdown in the black bar above your video list and click 'Monetization'
- Click 'On' in the monetization dropdown (note: to change ad settings in bulk, click 'Add edit')
- Click 'Update videos' and check the box to confirm you understand the consequences of the action and 'Update videos'