To write an employee thank-you letter, begin by greeting the individual formally or casually, succinctly explain the reason for the appreciation, specify the jobs that have been done effectively, and include any appreciation from others in the organization. Towards the end, reiterate your appreciation and sign off.
Preferably, you should hand write the thank-you letter to personalize it, instead of printing it. Also, write it on a beautiful card or stationery, rather than on the company's letterhead.
When penning the letter, first greet the employee with a formal salutation by adding "Dear" before his name or casually by just addressing him by his name.
In the first sentence of the opening paragraph, let the employee know that he is being thanked for a specific job using phrases such as "Thank you very much for" or "I would like to appreciate you for," followed by a description of the work for which you are thanking the employee. Also, express how the employee has become an integral part of the organization through his efficient work.
In the next paragraph, mention any praise from other bosses or clients. Also, include a note of some reward for the work done well, such as a lunch party for the employee's department. End the thank-you letter by appreciating the employee again using phrases such as "Thank you once again for" or "I genuinely appreciate," with a summary of the work for which you are expressing appreciation.
Finally, sign off formally using a complimentary close such as "Yours sincerely" or "Sincerely." Alternatively, just sign your name.