Similar to business or employment_related correspondence, military correspondence also has set standards for the closing (also called a “valediction”) which one should present before one’s signature. If your company conducts business with the military – or if you are applying for a job in the military – you should be aware that “Very Respectfully” (often abbreviated as “V/R”) is used in written and emailed correspondence between military members.
When you know the recipient’s name, sign it “Sincerely yours” or just “Sincerely”, or in the US “Yours truly” is acceptable. Don’t try anything more cutesy or friendly unless a) you know the recipient quite well and are certain you can be informal without seeming disrespectful, or b) you have a “trademark” letter ending that’s part of your public persona (and the talent and popularity to pull it off). Signature and printed name: Signing your name is a minimal assurance that you stand behind what was written.