Mention the position you're resigning from and the effective date of your resignation. This resignation letter should include details of the resignation like date and reason for leaving.You can use this resignation letter sample as a base to write a letter with your own name, dates, and other information. 1. Enter the date on the letter. Add contact details, company name, and date. The California Department of Public Health is dedicated to optimizing the health and well-being of Californians. The position will remain open until filled.