Dear Ankita,
Greetings of the day!
Appraisal forms and systems are generally designed to suit company requirements. Therefore, using downloaded appraisal forms from the internet will only help in making this very important exercise a form-filling routine work with no ROI. Instead of doing that, my suggestion would be that you read the book "Performance Management and Appraisal Systems" by Dr. T V Rao. Not only does that book give very good insights into what PMS is all about, but rigorously following what has been said will also help you in designing an appraisal system that is specific to your own company.
In case you need any help with designing the system, please feel free to write to me at avinashvadi@gmail.com.
Warm regards,
Avinash V Rao