Dear Kegotumi,
Please check Chapter IX "Working Hours" and Chapter X "Wages and Payment" in the Bangladesh Labour Act 2006 to have a clear idea about your query. If any worker is absent for more than five times, and you have issued a warning letter and imposed any punishment for their absence exceeding three times, then after conducting a proper inquiry, you can terminate the employee. You do not need to provide these details in the Appointment letter. You can include all these clauses in your company's Discipline Policy within the HR Manual.
I hope I have clarified your query. If you have any further queries, please do not hesitate to ask in this forum.
All the best.