Double-line signature paper is a common business letter format, which is mainly used for formal business letters, reports, memos and so on. The correct writing method can make your letter look more professional and formal. The following are the correct ways to write some basic double-line stationery:

1. Letterhead: Letterhead usually includes your company name, address, telephone number and email address. This information should be clear and accurate, and located at the top and center of the stationery.

2. Date: The date should be written at the bottom of the stationery in the format of "MM/DD/YY".

3. Recipient information: The information of the recipient should be written below the date, including their name, position, company name and address.

4. Address: Address should be in formal language, such as "Dear Sir/Madam" or "Dear Doctor".

5. Text: The text should be clear and concise, using formal language. The beginning of each paragraph should be indented for ease of reading.

6. Ending: The ending usually includes words of thanks and your signature. The signature should be legible.

7. Attachments: If there are attachments in the letter, please indicate them at the bottom of the letter.

Proofreading: Before sending a letter, you should proofread it carefully to make sure there are no spelling or grammatical mistakes.

The above is the basic writing method of double-line letter label paper. It should be noted that different companies may have different letter signing paper formats, so you should follow your company's regulations when writing.