Mohit just leave study and start your own business. It's good for your future and secure your present. Just think about my suggestion!

Hello aspirant.
I am glad to learn about your keen interest in studies.
As per your question i do understand your situation.
Yes, there are many apps and videos available online for 11th and 12th.
Here are a few apps which you can use:
Byjus learning app
Youtube.
There are tons of videos and lectures available on youtube.
Brainly
Vedantu

I hope this answer was helpful.
All the best.