AWOL Letter for the employee that leave without resignning the company.

Hi!
Good day,
Can you help me how to write a proper AWOL Letter for the employees that did not already reported in his duty without giving a resignation letter?
Thank you!

hello!
My boss want me to write a MEMO (AWOL Letter) for our two employees who did not already reported on their working schedules since this employees have already decided to quit on their job for some reasons. But they did not filed a resignation letter. I don`t know what should be the proper or correct letter i have to write.
Hoping for your quick response. Thank you!