If you are sending a letter to the registered office of a company, you must put the term "A / A", which is the abbreviation of "to the attention of". This will ensure that the letter reaches the correct recipient. Addressing a letter with the phrase "to the attention of" is easy once you know what to do.
Steps
Method 1 of 1: Put the recipient's details in the envelope

Step 1. Write "To / A" followed by the name of the recipient
The line where you enter the term "To / A" should always appear at the top of the recipient's address, just before the name of the person to whom you are sending the letter. Use a colon after "A / A" to make it perfectly readable. This line will tell the postman exactly who the letter is intended for.
- For example, write "To / A: John Smith", where "John Smith" can be replaced by the name of your recipient.
- As an alternative, you can write the entire sentence "to the attention of".

Step 2. Write the name of the company or organization below
The name of the company where your recipient works should go below the "A / A" line. You should write the business name on the second line of the recipient's address.
- If the company is large and the person you are writing to works in a particular department, include the name of that department on a separate line before writing the company name.
- Note that generally failing to include the name of the company on the envelope will not prevent your letter from being delivered. However, your letter will look less professional and may not be delivered in a timely manner if you do not include the name of the company.

Step 3. Add the address below the company name
The full address must be entered on one line. Be sure to include direction signs (such as "East" or "West"), suite number, or unit number. Suite and unit numbers should not be placed on a separate line unless absolutely necessary.
Make sure you know the exact address of your recipient's workplace. Many businesses that are located in large or multi-story buildings will include a suite number in their address. Including this number is crucial

Step 4. Put the city, state, and zip code on the bottom line
If you know the "ZIP + 4" code, include it to make sure your letter will reach the correct address.

Step 5. Check your address to determine that you have spelled it correctly
When you have verified that all the information is correct, put a stamp in the upper right corner and send your letter.
Advice
- A convention similar to "A / A" is "a / c", which means "in care of." These letters are used to designate an intermediary who will be responsible for delivering the mail to the final recipient. For example, suppose you want to send an envelope to John Smith, but you only have the address of his mother, Mary Smith. When entering your recipient's details, write "John Smith" on the top line, "a / c Mary Smith" on the next line, and Mary's full address on the next lines.
- Different countries have preferred standards for mailing. Although the general format is similar, you should verify the exact specifications of the postal service in your country.
- The most common thing among most postal services is that you enter your recipient's information in capital letters. This makes the output obtained from the mail processing equipment more reliable.