The proper form is "Dear Mr. President."
In newspapers, the President of the United States should be addressed as "President [Last Name]." For example, "President Biden" would be the proper way to address the current U.S. President, Joe Biden.
The accepted proper way to address the U.S. President is "Mr. President"... and undoubtedly at times in the future, "Madam President".
Unless you're being extremely formal (like some sort of ceremony), use "Mr. President". That seems to be standard at press conferences and such.
what is the proper way to address the mayor
The proper way to address the conductor of a symphony orchestra is 'Maestro.'
Address the school board as a whole using terms like "Members of the School Board" or "School Board Trustees." When speaking to an individual member, address them as "Mr./Mrs./Ms. [Last Name]" or using their official title, such as "Board President" or "Board Chair."
the proper way to address the Queen is by "your majesty" or Ma'm, pronounced like "ham'
You may address the letter in either way. However, to be "proper" you should always address it Dear Mr. President. you either type it or write it then find the White House address and send it in the mail Yes, but how do you address it, Dear Mr. president, Dear Mr. Obama?
"Your honor"
usted. or ustedes.
Gentlemen
The proper way to address a Doctor of Osteopathic Medicine (DO) (not Doctor of Osteopathy) is Doctor (Dr.) since they are medical physicians.
Master John Doe