What letters are capitalized in the salutation, "TO: Whom it may concern"?

Question

Grammar, spelling, capitals

Answer 1

If you are writing a letter, it should be -

To Whom It May Concern:

Either a colon: or semicolon; is acceptable. I would also recommend addressing it a little more carefully if you want the proper person to read it, using the correct name or title whenever possible - try using
Dear Human Resource Manager,
Dear Customer Service Manager,
Dear Sir or Madam,

The TO: is only used in email headings, in which case you would write the email address, and then put the subject of your letter in the Subject: line.

Answer 2

There is no reason to capitalize anything other than the T in "To" and, since you are addressing it to someone you do not know, it needs to be followed by a colon, not a comma, as in
To whom it may concern:

Answer 3

If it is the heading of a medical certificate, etc. I would underline it and write as: To Whom it May Concern.

Answer 4

To whom it may concern,