Simply replace the unfilled areas such as "[]" and "[date]" with your information.
Dear [name],
It is with great pleasure that I announce to you that I have recently been [transferred/promoted] to [name of position] of the [name of organization/department/branch].
Please allow me to introduce myself. My name is [name], and I have, [#] years experience in the [type field] field. This has given me great insight to the needs of our customers. I believe that it is our customers that make us a success and I work daily with that philosophy as my guide.
[Name of organization/branch] is known for its delivery of good quality of service and I intend to uphold that reputation. With great enthusiasm, I am looking forward to servicing your [type of needs i.e. financial/insurance/etc.] needs.
Please don't hesitate to contact me at [phone #/email address] if I can be of any assistance to you. I am eager to work with all of you and hope that you feel the same.
Sincerely,