Hello bhoumik,

You can download the previous year cbse class 12th all subjects papers and sample papers by following the link mentioned below. You can download them in PDF format as well :

https://www.google.com/url?sa=t&source=web&rct=j&url=https://school.careers360.com/boards/cbse/cbse-previous-year-question-papers-class-12/amp&ved=2ahUKEwip-rGHo9L3AhXdSmwGHa4RDKUQFnoECAgQAQ&usg=AOvVaw26ZSh0fQLV6dzPD5U4n2qD

https://www.google.com/url?sa=t&source=web&rct=j&url=https://school.careers360.com/boards/cbse/cbse-previous-year-question-papers/amp&ved=2ahUKEwip-rGHo9L3AhXdSmwGHa4RDKUQFnoECAoQAQ&usg=AOvVaw3q8D7l2aNrVFtPEB2ELoBs

Central Board of Secondary Education releases the previous year question papers of Class 12. Students can download these CBSE Class 12 previous year question papers from the official website of CBSE , i.e. cbse.gov.in. The above mentioned previous years CBSE question papers are provided for all the subjects including Hindi, English, Physics, Chemistry, and so on.

I hope that this will help.