Hello akshit,thanks for asking this question on this platform.if you want to complete notes of any particular coaching then you have to buy their distance learning program in which they provide all the covered syllabus notes with practice papers and that is of good quality too .but you can't get all the notes from any website online so for getting you have to purchase them .

Thanks 

All these can be purchased online on theor official website or sinply by taking photocopies from your folks. 

It is not readily available for free for download  

You can contact coaching institutions for further assistance in buying those notes and materials. 

For sample papers you can check below. 

https://engineering.careers360.com/articles/jee-main-sample-papers