Dear Sonali,
In what capacity do you work in your company? What is your designation?
If you are from HR then be it known that preparation of Job Description (JD) is your job. Please sit with each and every individual and understand what do they do. Write it down. Scores of formats of JDs are available on this forum. Choose one amongst them.
Secondly, preparation of KRAs of the subordinates is the job of each HOD. However, as an HR professional, you may check whether it meets the SMART principle or not.
Lastly, nothing wrong per se for asking help for the sending mail. However, it would be proper if you prepare the draft and upload it here. Asking for a ready-made draft is nothing but spoon-feeding. How long you wish to do that?
Thanks,
Dinesh Divekar