Pick the reason you are leaving for sample letters you can copy, tips on what to say and what to leave out, and answers to common questions.
The date, who it is addressed to, a clear statement that you are resigning from your role, your last working day based on your notice period, an offer to hand over your work, and a polite thank-you. Keep reasons short.
No. A reason is optional and it is fine to keep it general. If you do give one, keep it brief and positive — the letter stays on your file.
Follow your company’s process. Most workplaces accept an email to your manager with HR in copy; some also ask for a signed letter or a request in the HR portal.