How to Write and Address a Letter: Formatting and Rules
To write and address a letter correctly, put your name and address in the top-left of the letter, add the date, then the recipient's name and address, a salutation, the body, a closing, and your signature, and on the envelope place your return address in the top-left corner and the recipient's address centered, with the city, state abbreviation, and ZIP code on the last line. Getting this right matters most when the letter is important enough that it must arrive, and be provable, every time.
How to Write a Letter: The Standard Format
The content of a letter changes with its purpose, but the format rarely does. Follow this order:
- Sender's name and address in the top-left corner. Depending on the letter's purpose you may include your company here.
- Date the letter is composed, written out with month, day, and year.
- Recipient's name, title, and address, left-aligned along the margin. Even though this appears on the envelope, including it on the letter itself is proper etiquette for formal business letters.
- Salutation. For a formal letter use the recipient's last name; if you do not know the name, "To Whom It May Concern" is the accepted standard.
- Body: an introduction paragraph, a paragraph stating the purpose of the letter, and a conclusion paragraph that often includes a call to action.
- Closing and signature: a valediction such as "Sincerely," "Regards," or "Thank you," space to sign, and your typed name.
- Enclosures: if the letter references attached documents, list them at the bottom.
A few extra rules of thumb: use a professional font such as Times New Roman, Georgia, or Cambria, keep text left-justified with single spacing, use clear professional language, and avoid all caps in the body for readability.
How to Address an Envelope Correctly
Correct addressing is what guarantees prompt, accurate delivery, because USPS mail sorting equipment reads envelopes from the bottom up and only processes about six lines. Here is the layout:
- Top-left corner: your name and address. This is the return address, where the piece goes if it is undeliverable. (On personal mail it sometimes appears on the back flap; for business letters the front corner is standard.)
- Center: the recipient's name on the first line, the street address or Post Office box on the next line, then city, state, and ZIP code on the last line.
- Use the two-letter state abbreviation. Sorting equipment reads only the first two letters of the state line, so spelling a state out invites confusion; the ZIP is read first, but the abbreviation removes ambiguity.
Must-Know Mail Regulations
What are the rules for mailing a letter?
A letter envelope should be flat, flexible, and machinable, meaning it can move through automated processing equipment. Envelopes with stiff enclosures, clasps, or outside attachments that prevent machine processing are assessed a non-machinable surcharge. A standard #10 envelope measures 9-1/2 inches long by 4-1/8 inches high, comfortably within letter-size limits. Current USPS rates, including any surcharges, are published on our rates page.
What is not allowed in the mail?
USPS prohibits mailing items that are unsafe to transport, such as explosives, ammunition, gasoline, and similar hazardous materials.
What is restricted in the mail?
Other items are restricted rather than banned outright: they can be mailed only under USPS conditions. Alcohol, live animals, and certain batteries fall into this category, so check the specific rule before sending.
What are the classes of mail?
USPS offers several mail classes, each built for a different need: First-Class Mail for everyday letters, Certified Mail for important documents that need proof, Priority Mail for faster delivery, and Express Mail for the fastest service. Each class has its own postage, and you can compare what each costs on our rates page.
When the Letter Must Be Provable
Most letters are routine. Some are not. Notices to agencies, employers, landlords, courts, and financial institutions are the letters where "I mailed it" has to become "here is the record." That is what Certified Mail is for: it documents that USPS accepted the piece, tracks it to delivery, and captures the recipient's signature with Return Receipt. Our online label tool prompts you for every required element, generates the correct label, and stores the proof of mailing, tracking, Electronic Delivery Confirmation, and Return Receipt signature in your complimentary 10-Year Compliance Archive.
Sending a stack of letters at once? Excel batch processing and API and SFTP automation handle high volumes, and our Print & Mail service prints, inserts, applies postage, and hands everything to USPS the same business day for orders placed by 5:00 PM Eastern. There are no monthly fees, no contracts, and no special equipment. Skip the trip to the Post Office and get started online today!
Frequently Asked Questions
How do you address an envelope so it gets delivered?
Put your return address in the top-left corner, the recipient's full name and street address or PO box in the center, and the city, two-letter state abbreviation, and ZIP code on the last line. USPS sorting machines read envelopes from the bottom up and only about six lines, so a clean, correctly formatted address block is what ensures delivery.
What are the parts of a properly formatted business letter?
The standard format is the sender's name and address, the date, the recipient's name and address, a salutation, the body in three paragraphs (introduction, purpose, conclusion), a closing such as "Sincerely," your signature, and a list of enclosures if documents are attached.
Why should you use a two-letter state abbreviation on envelopes?
USPS sorting machines read only the first two letters of the state line, so writing a state name out in full can be misread during automated sorting; the standard two-letter abbreviation eliminates that risk.
What makes an envelope non-machinable?
An envelope is non-machinable when it is not flat and flexible or has attachments, clasps, or irregular enclosures that prevent it from moving through automated processing equipment, and USPS applies a surcharge to such pieces.
How do I prove an important letter was mailed?
Send it by Certified Mail: you receive a USPS acceptance record, a tracking number, delivery confirmation, and, with Return Receipt, the recipient's signature. Online services keep all of that documentation searchable in an archive, so proof is available years later if a dispute arises.
What is the difference between First-Class Mail and Certified Mail?
First-Class Mail is the standard class for everyday letters; Certified Mail is First-Class Mail plus a certified fee that adds tracking, an acceptance record, and a signature requirement at delivery, which is why it is used for legal notices and other documents that need proof of mailing and delivery.