When using "To Whom It May Concern" in a letter, each word is typically capitalized. The phrase is followed by a colon. For letters relating to job inquiries, other salutations are also acceptable. For instance, "Dear Hiring Manager" followed by a colon is an acceptable greeting.
It is also acceptable to use no greeting in a letter of inquiry about a job. Using no salutation or using a generic phrase such as "To Whom It May Concern" typically occurs when the person writing the letter does not know to whom to address it. Etiquette for cover letters accompanying resumes varies by the job sought. All cover letters should include the full name and contact information of the job seeker, along with the specific job the letter regards.