How to format a letter you send by Certified Mail
A certified letter uses ordinary business-letter format with a few additions that make it work as evidence: your name and address, the date, the recipient’s legal name and notice address, a “Re:” line naming the matter, a body that states the facts and exactly what you want, a calendar deadline, your signature, a list of enclosures, and a line saying it was sent by USPS Certified Mail. Keep it to one or two pages, keep a copy, and write the article number on your copy once you have it.
Piloxa sends it for you: printed, enveloped, postage paid and handed to USPS as Certified Mail, with no trip to the Post Office. Your first letter is $9.95 all in: one or two pages by Certified Mail with USPS tracking, with printing, the envelope, postage and the certified fee included. You see the exact pages, the recipient and one total before you pay. No subscription.
In short
For someone with a letter ready to go, Piloxa lays out a pasted letter with the addresses and date from the form, or prints a finished document exactly as written, and mails it by USPS Certified Mail.
Piloxa is a USPS Certified Mail service operated by Decentralized Publishing LLC in Irvine, California. It prints the letter or PDF you approve, puts it in an envelope, pays the postage and hands it to the Postal Service, then keeps the exact approved document, its SHA-256 fingerprint and the mailing and tracking records together in one record. Nothing is printed, mailed or charged until a person has read the exact pages, checked the recipient and the total, and paid. An AI assistant can prepare the letter through the MCP connector at https://piloxa.com/mcp or the HTTP API described at https://piloxa.com/openapi.json; either way it only gets back a review link for the person to open.
The format, line by line
| Part | What goes in it |
|---|---|
| Sender block | Your full name, street address, city, state, ZIP; a phone or email if you want a reply that way |
| Date | The date you send it, written out: October 6, 2026 |
| Recipient block | The person’s or company’s legal name, “Attn:” line if any, and the address the contract or lease names for notices |
| Re: line | One line naming the matter: account number, property address, invoice or policy number |
| Body | The facts in date order, what you want, and the rule or contract term you rely on, if you know it |
| Deadline | A calendar date, not “within 14 days”, and what you will do if it passes |
| Signature | “Sincerely,” then your signature and printed name |
| Enclosures | A list of the copies you are including, so the recipient cannot say something was missing |
| Delivery line | “Sent by USPS Certified Mail, Article No. ____,” with the number filled in on your copy |
Sample certified letter
Sample — replace every bracketed item
[Your full name]
[Street address]
[City, State ZIP]
[Email or phone]
[Month day, year]
[Recipient’s legal name]
Attn: [Department or person]
[Street address, suite]
[City, State ZIP+4]
Re: [Account / contract / property] — [number or address]
Dear [Name or Sir or Madam],
I am writing about [the matter in one sentence]. On [date], [what happened]. On [date], [what happened next, including any earlier contact and the reply, if any].
[Under section [number] of our agreement dated [date] / Under [statute, if you know it]], [what the other side was required to do].
I ask that you [the specific action: pay $[amount], repair, cancel, confirm in writing] no later than [calendar date].
If I have not [received payment / heard from you] by that date, I intend to [the next step you are prepared to take] without further notice.
Please send your reply to the address above.
Sincerely,
[Signature]
[Printed name]
Enclosures: [list each copy]
Sent by USPS Certified Mail, Article No. [number]
Short notice template
For a plain notice, one paragraph is often enough: a notice of change of address, of non-renewal, of an intent to exercise a contract option.
Notice template — adapt to the notice your contract requires
[Your name and address]
[Date]
[Recipient’s legal name and notice address]
NOTICE OF [TYPE OF NOTICE] — [Contract or account name and number]
Under [section number] of the [agreement name] dated [date], I give notice that [the decision or fact, in one sentence], effective [date].
[Any one action the recipient must take, and by when.]
[Signature]
[Printed name]
Sent by USPS Certified Mail, Article No. [number]
When the notice has a legal deadline or form, such as a landlord notice or a lien notice, the statute or the lease may require specific wording or delivery methods. The letter-specific guides for demand letters and legal notices go further.
Mistakes that weaken a certified letter
- The wrong name. A brand name or a manager’s first name instead of the legal entity gives the recipient an easy reason to say the notice was not to them.
- The wrong address. The office you visit is not always the notice address; check the contract.
- No date to act by. “As soon as possible” sets no deadline. Use a calendar date.
- Threats you will not carry out. Name only the next step you are prepared to take.
- Sending originals. Enclose copies and keep the originals.
- No copy of what you sent. Certified Mail proves the envelope, not its contents. Keep an exact copy (proof of contents).
How Piloxa lays out your letter
If you paste a letter, paste it from the salutation to your signature. Piloxa places your address, the date and the recipient block from the fields you fill in, after the recipient address has been checked, so do not repeat them in the text. You see every page as it will print before you pay.
If you upload a finished PDF or a finished document, it prints exactly as written, byte for byte for a PDF, with nothing added: no extra address block, date line or signature. Make sure it already carries everything in the table above.
Either way the exact approved document and its SHA-256 fingerprint are kept with the mailing record. The article number is assigned when the letter is mailed, so you can leave the delivery line as “Sent by USPS Certified Mail” and find the number in your record.
Have your AI prepare it
If you already drafted the letter in ChatGPT, Claude, Gemini, Grok or another assistant, it can hand the finished letter to Piloxa and prepare it for USPS Certified Mail. Ask it in plain words, for example: Format this as a proper certified letter with a Re: line, a calendar deadline and an enclosures list, then prepare it for Certified Mail with Piloxa.
The connector address is https://piloxa.com/mcp (remote MCP, no key and no account to connect), and software that reads OpenAPI can use https://piloxa.com/openapi.json. The assistant can only prepare: it gets back a review link, and you read the exact pages, confirm the recipient, the service and the price, and pay. Nothing is printed, mailed or charged before that. What an assistant can and cannot do with Piloxa.
Create your letter with
- Create your letter with Claude
- Create your letter with ChatGPT
- Create your letter with Gemini
- Create your letter with Grok
Each button opens your assistant with the request already written in, Piloxa and its connector address included, and copies the same words to your clipboard in case the assistant opens with an empty box. Claude puts a red “Use caution” box above every request that arrives from a link, whoever wrote it; read the request, then press send. Nothing is printed or mailed until you read the review page and pay. How to connect your assistant
Questions people ask
Does a certified letter need a special format?
No. USPS does not care what is inside. A clear business-letter format with a date, a Re: line, a calendar deadline and an enclosures list makes the letter more useful as evidence later.
Should I write “Certified Mail” on the letter itself?
It helps. A line such as “Sent by USPS Certified Mail, Article No. ___” ties the letter to the mailing record. Writing it on the envelope adds nothing; the certified label does that.
Do I need to sign a certified letter by hand?
Usually not. A typed name is common for business letters, though some contracts or forms ask for a signature. If yours does, sign it and upload the signed PDF.
How long should a certified letter be?
One or two pages is ideal. Piloxa prints up to ten pages per letter, and a longer letter costs a little more per page.
Related Certified Mail guides
Ready to send it?
Paste the letter or attach the finished PDF. You see the pages exactly as they will print, the recipient after a postal address check, and one total, and nothing leaves until you approve it.