Hi Bharti,

There must be some students who are taking and who took some guidance from this application. They might have been able to understand a lot of topics but at the end of the day, the self notes and revisions, work more than any application. BYJU's is quite helpful for students of not just school but college too, no doubt. But I don't think so one can completely count on this for the entire preparation for an exam like UPSC IAS. 

Hope the answer helped. Good luck!