A resignation letter is a formal document submitted by an employee to notify their employer of their decision to leave the company. It typically includes the employee's clear intention to resign, the proposed last working day, and, if desired, a brief explanation of the reason for leaving, which may be personal or professional. The letter often expresses gratitude for the opportunities, experience, and growth provided during their time with the company. Additionally, the employee may offer assistance in transitioning responsibilities to ensure a smooth handover. The resignation letter, signed by the employee, serves as a professional courtesy to formally inform the employer in advance of their departure, ensuring proper planning for the transition.