I think you won't be eligible under the condition that You should have passed 12th boards appearing for the first time in 2019 or 2020. You can check official website for exact criterias of eligibilty. Many conditions are there. You can also use this link: https://engineering.careers360.com/articles/jee-advanced-eligibility-criteria

Yes buddy you can apply for jee for sure in 2020 as a fresh candidate. But there is not application for JEE advanced. You need to crack JEE mains first to get eligible for JEE Advanced. Just see the official rules and form filling date and everything and stay in touch with the official website to be up-to-date. 

Best wishes. Thank you.