After satisfying all YouTube conditions, you are eligible to apply to the Partner Program. To do this, the following actions must be taken:
1. Go to YouTube Studio
2. Click on the Monetization from the navigation bar on the left
3. If you're eligible to apply, you will see a blue button. Click it!
4. Review the terms of YPP
5. Set up Google AdSense account and link it to your channel
6. Now you will have to wait. YouTube will review your account and then inform you about their decision through email