Follow the business letter format. Include your address at the very top left of the letter, omitting your name and title. Include the date immediately below your address, following the format of the parent country where the corporation operates. For example, if you are writing to an American company, use the American date format: month, day and year. February 12, 2011.
Find the name of someone with decision-making power at the corporation you are addressing. Contact the sales representative or account manager assigned to your company to inquire about whom you should address your letter.
Employ personal titles. For instance, if you are addressing a woman, such as Ms., Mrs., or Miss, include this at the beginning of the inside address line. Include the street address for the company underneath the name of the recipient. Follow the U.S. Post Office format. Place a one-line space between your address and the recipient's name.
Space down one line. Type your salutation, using the full name and title of the person you are addressing. Insert a colon after the salutation. For example, if you were writing to Jane Doe, your salutation might read:
Dear Ms. Jane Doe:
Begin the body of your letter one line after the salutation. Introduce yourself and your company in one or two sentences. Include a reminder of any personal introductions or work contacts you have had with the recipient, if you are acquainted.
Make your request for credit in the first paragraph. Describe the total dollar amount and detail what products or services you are requesting the credit for. Limit this part of your credit request to one or two sentences.
Detail the terms of your request in a new paragraph. Explain, in further detail, why you are requesting credit. Include any details about terms that you've discussed with other employees of the corporation.
Conclude your letter with a new paragraph. Restate your request for credit and give a date by which you need a response. Include a brief explanation for why you need the response by that date. Close your letter formally, using a closing such as "Sincerely" or "Respectfully." Provide room to sign the letter between the closing and your printed name and title.