hi,

see I understand you are facing difficulty at studies since the schools are closed and it may not possible to take tuition classes for every one. however there is various online resources and coaching facility available for students who are preparing for 12th exam.

free video courses are available on you tube, you have to search the topics and see the lecture series.

you may look for online classes at  byju, vedantu, unacademy, toppr like platforms, but you have to pay as per tuition classed you would take.

so do a research by your self and select the course.