If it's a "temporary staff," why do you give an Appointment Letter? Better frame a Training/Apprenticeship Policy (Include the objectives, procedures, manual, etc.). Issue a Letter of Apprentice to temporary employees, with a period of 6 months or 1 year, depending on the nature of the work. Review their performance after the prescribed period, issue a Letter of Appointment as permanent employees. Temporary employees are not on the rolls of the company and should not be subject to or under the purview of any contract (Letter of Appointment). Once they finish the apprenticeship, we are bound to bring them on a roll basis based on their performance. Regards, Sriram.