Plus, a formal letter format tends to convey a sense of professionalism ... check their LinkedIn or call the company to speak with a receptionist and ask who the letter should be addressed to.

Assuming that you can stick around for the standard ... "The format in which you formally resign will vary from company to company. Some will require a written letter, others will require you ...

Your grievance letter should follow a formal business letter structure. Include the date at the top, followed by your name ...