Definition: To Whom It May Concern is a letter salutation that is used in business correspondence when you don't have a specific person to whom you are writing.
It is appropriate to use To Whom It May Concern when making an inquiry, but you don't have a contact person to address your letter to.
When addressing a letter To Whom It May Concern, the entire phrase is typically capitalized, then followed by a colon:
To Whom It May Concern:
Letter Greeting Options:
There are alternatives you can use for letter salutations, including "Dear Hiring Manager" for cover letters, and leaving off the greeting from your letter.
If you leave off the salutation, simply start with the first paragraph of your letter. Here are examples:
Susannah addressed her cover letter To Whom It May Concern because there was no contact person listed in the job posting.