Dear XXX:

I would like to inform you that I am resigning from my position. My last date of employment will be (Date).

1. Use Friendly Terms

For your neighbour or co-worker, start your letter with an informal style, e.g. "Dear Mary,"

Dear XXX,

I would like to let you know that I am leaving my position at (Company) with effective (Date). I will be starting a new position at another company next month.

Dear Mr./Ms.XXX:

This is to inform you that I am resigning from my position as (Position) for (Company), effective (Date).

Dear Mr./Ms.XXX:

This is to inform you that I am resigning from my position as (Position) for (Company), effective (Date).

Dear XXX 

This is to inform you that I will be leaving my position with (Company) effective (Date).

Dear XXX:

The purpose of this letter is that I am hereby tendering my resignation to you. The last day of my employment will be (Date).

Dear XXX:

I would like to inform you that I am resigning from my position. My last date of employment will be (Date).

Dear Mr./Ms. XXX:

I want to thank you for all you have done for me here at (Company). It's been a pleasure working with you, and representing the company as your (Job Title).

Dear Mr./Ms. XXX:

Please accept this letter as resignation of my position as (Position), effective (Date). I am offering one month notice - this will give you an opportunity to find a suitable replacement. if you would like, I am more than willing to provide training and orientation to the newcomer.

Dear Mr./Ms. XXX:

I am tendering my resignation to you and (Date) will be my last day of employment.