Try not to be tempted to begin your professional letter with informal salutations like “Hello,” “Greetings,” “Hi There,” or “Good Morning” if you don’t know the name of your contact person.
While those informal styles of greeting are fine for casual emails to friends or even for more formal emails you might send out to groups of people, in a professional letter you’ll need to use a personal salutation, one with either a first and/or last name (“Dear Mr. Doe”) or a job title (“Dear Hiring Manager”).
Always make sure to double-check the spelling of the letter recipient's name. Otherwise, you'll be making a poor impression from the start of your letter. As well, don't neglect to include the period after "Mr." and "Ms." Follow your salutation with a colon (e.g., "Dear Ms. Doe:").
Examples of Professional Letter Greetings
These greetings are all suitable for professional communications.
Dear Firstname Lastname; e.g., Dear John Doe
Dear Mr./Ms. Lastname; e.g., Dear Mr. Doe or Dear Ms. Doe
Dear Mr./Ms. Firstname Lastname; e.g., Dear Mr. John Doe or Dear Ms. Jane Doe
Dear Hiring Manager
Dear Sir or Madam
To Whom It May Concern
Dear Human Resources Manager
Dear Company Name Recruiter; e.g., Dear ABC Company Recruiter
https://www.thebalancecareers.com/professional-letter-greetings-2062310