Retirement letters are written to the Company/Management and Staff as the person is retiring from a job. This is a parting letter to the organization or the people you have worked with for some time.
The beginning of the letter should state your date of retiring as well as mention the number of years of your service in the organization.
While writing to the organization, the letter must include official details such as the reasons for retirement, briefly highlighting the good things about your association with the organization. The letter must also include your future plans and address for communication etc.
While writing to the members of the organization, the retirement letter can highlight the association and the happy times you have spent with them. Though the letter may be addressed to everybody, make the tone warm and personal, as if it is written to include each individual.
In both cases, it is good to thank the people who have helped you to learn and grow in the organization. This is not the time and place for letting steam off about some grudges you may be nurturing. Parting should always be a smooth one, so keep the tone cordial and warm.
As you end the letter, briefly mention your re-settlement or future plans and ways to communicate with you in the future.
Close the letter thanking the people and the organization and if possible offer to keep in touch with the people.