You letter should be written after every interview with an employer. Send the letter within a week after the interview.Learn how to write an employee appreciation letter with these templates and examples. Download the template for free (PDF or Word). I want to congratulate you personally for completing your year with < company name >. It has been a pleasure working with you. Thank members of Congress after your interactions to form a good, working relationship. Following an interview, promptly (within 2 business days) write the interviewer a letter expressing appreciation and thanks for the interview. Cover only one topic per letter and keep your letter to one page. • If you want a response, specifically ask for one.