Important Language for a Business Inquiry Letter
The start: "Dear Sir or Madam" or "To Whom It May Concern" (very formal, used when you do not know the person to whom you are writing). If you know your contact already, that's better than being anonymous.
Giving reference: "With reference to your advertisement (ad) in..." or "Regarding your advertisement (ad) in..." Give the company context to why you're writing, right away.
Requesting a catalog, brochure, etc.: After the reference, add a comma and continue, "Could you please send me information on..."
Requesting further information: If you have more that you're seeking, add, "I would also like to know..." or "Could you tell me whether..."
Summary call to action: "I look forward to hearing from you..." or "Could you please give me a call between the hours of..."
Closing: Use "Sincerely" or "Yours faithfully" to close.
Signature: Add your title on the line following your name.
An Example Hard-Copy Letter
Your Street Address
City, Zip code
City, ST Zip code
September 12, 2018
To Whom It May Concern:
With reference to your advertisement in yesterday's New York Times, could you please send me a copy of your latest catalog? Is it also available online?
I look forward to hearing from you.
Your Job Title
Your Company Name