A resignation letter is a formal document that an employee submits to their employer to officially announce their intention to leave the company. It serves as a notice and typically includes the employee's decision to resign, the date of the last working day, and a brief explanation for leaving, though this is optional. In addition, the letter may express gratitude for the opportunities, experiences, and growth gained during employment. It may also offer to assist with the transition process, ensuring a smooth handover of duties. The letter is signed by the employee and is an important professional courtesy that helps maintain positive relationships with the employer.