Dear Anirudh,
Please write a simple letter addressed to your ex-employees or their legal heirs in simple language, stating that they have worked with our organization from (date) to (date). The organization has declared a bonus percentage of 8.33% to 20% (whatever your company declares) for the year (year). The total bonus amount is (amount), for which we have attached a cheque.
You can attach the cheque and send it to the concerned ex-employee through a courier service. This will help in maintaining records for dispatching the bonus cheques. Additionally, please make a note on the Form C (Bonus Register) that the cheques have been couriered for employees who have left the organization. Include the cheque number, cheque date, and courier register number for further documentation support.
Wishing you all the best.