One wrong line on the envelope can delay your letter by weeks.
When the letter is important, that delay can cost you money.
Maybe even a deadline.
This guide shows you exactly how to address:
Letters to an attorney
Letters to a judge or court
Letters to the IRS and other government agencies
Immigration and insurance claim letters
Certified mail with proof of delivery
(This is general information, not legal advice. For high-stakes matters, consult a licensed attorney.)
The Short Answer
To prove your letter was delivered, send it by USPS Certified Mail, and add a Return Receipt if you want a signature.
You keep a receipt and tracking number as proof.
Below: when you need it, how it works, and how to address the envelope.
Why Addressing Matters More for Official Mail
A birthday card that arrives late is no big deal.
A legal notice that arrives late is a different story.
Official letters often come with:
Deadlines
Proof requirements
Strict addresses that cannot be guessed
If the address is wrong, you may have no proof you ever sent it.
The 5 Golden Rules for Official Letters
1. Use the address printed on the notice.
If an agency sent you a letter, reply to the exact address on it.
Never assume a general address works.
2. Include reference numbers.
Case number. Notice number. Claim number.
Put them in the first lines of the letter, and in the “Attn:” line on the envelope if the instructions say so.
3. Use the correct title.
Titles show respect, and in legal settings they also show you did your homework.
4. Keep it clean and typed.
Print the address. Don’t handwrite it if it can be avoided.
5. Keep proof.
Make a copy of everything.
Keep the receipt and tracking number.
How to Address a Letter to an Attorney
On the envelope:
Jane Miller, Esq.
Miller & Associates, LLP
450 Main Street, Suite 200
Chicago, IL 60601
In the salutation:
Dear Ms. Miller:
Pro tip: Use either “Esq.” or a courtesy title like Ms. or Mr. on the envelope, never both.
Writing to a law firm with no specific attorney?
Use: Dear Counsel: or Dear Sir or Madam:
How to Address a Letter to a Judge or Court
On the envelope:
The Honorable Robert Chen
Judge, Superior Court of California
County of Los Angeles
111 N. Hill Street
Los Angeles, CA 90012
In the salutation:
Dear Judge Chen:
Important: Most courts do not allow direct personal letters about an active case.
Filings usually go to the clerk of court.
Check the court’s rules first.
How to Address a Letter to the IRS or Another Government Agency
The rule is simple:
Use the exact address on your notice.
IRS addresses depend on your state, the form, and the type of notice.
The wrong address can slow everything down.
Include in your letter:
Your full name and address
The notice number (usually in a corner of the notice)
The tax year in question
Your Taxpayer Identification Number (never put your full SSN on the outside of the envelope)
Salutation:
Dear Sir or Madam: is acceptable when no name is given.
Strongly consider certified mail for anything involving taxes, penalties, or deadlines. We’ll cover how below.
How to Address Immigration Letters (USCIS and Others)
Immigration mail is strict.
Filing addresses change based on the form and location.
Before you mail anything:
Check the current filing address in the form instructions
Match your A-Number or receipt number on every page
Send with tracking
Mistakes here can mean rejected filings.
If your case is complex, a licensed immigration attorney can review it before you send.
How to Address an Insurance Claim or Demand Letter
These letters often matter in disputes, accident claims, and refunds.
Envelope:
Claims Department
Attn: Claims Manager
Blue Harbor Insurance Company
PO Box 12345
Dallas, TX 75201
Include in your letter:
Policy number
Claim number
Date of incident
A clear request, with a deadline for response
Salutation:
Dear Claims Manager:
Then keep it factual, with no emotion.
Not sure how to word the first line? Here are examples that work →
What Is Certified Mail, and When Should You Use It?
Certified Mail is a USPS service that gives you proof of mailing and a record of delivery.
You get:
A receipt when you send
A tracking number
A delivery record kept by USPS
Add a Return Receipt if you want a signed proof that someone received it.
Use certified mail for:
Legal notices
Tax correspondence
Landlord and tenant disputes
Insurance and billing disputes
Contracts and official requests
(Fees and options change. Check USPS for current details.)
How to Address and Send Certified Mail: Step by Step
Step 1: Address the envelope normally, with the recipient in the center.
Step 2: Put your return address in the top left.
Step 3: Fill out the Certified Mail form at the post office, or use the label option.
Step 4: Add Return Receipt if you need signature proof.
Step 5: Keep the receipt and tracking number in a safe place.
Step 6: Track it online until delivery is confirmed.
Pre-Send Checklist
Before sealing, check:
✅ Is the address exactly as shown on the notice?
✅ Is the recipient’s title correct?
✅ Are reference numbers included?
✅ Is your return address on the envelope?
✅ Did you sign the letter?
✅ Did you make a copy?
✅ Are you using certified mail if proof matters?
6 Costly Mistakes to Avoid
1. Using an old address
2. Forgetting the case or claim number
3. Skipping tracking on important letters
4. Putting sensitive numbers on the outside of the envelope
5. Mailing at the last minute
6. Not keeping a copy
Frequently Asked Questions
Is certified mail legally required?
Sometimes. Contracts, leases, and court rules may require it for certain notices.
Always check your document or ask an attorney.
Can I send a legal letter by regular mail?
You can, but you will have no proof of delivery.
For important matters, certified mail is safer.
What if I don’t know the person’s name?
Use the department or title.
Example: Attn: Records Department or Dear Claims Manager:
How long should I keep proof of mailing?
Keep it at least until the matter is fully resolved, and often longer for tax-related items.
Your Mail Is Protected. Is Your Message Strong Enough?
The best address in the world won’t help if the first line loses the reader.
Applying for a job? Answering a company? Writing to a business for the first time?
The opening line is where most letters win or lose.
👉 SEE THE OPENING LINES THAT GET LETTERS READ →
Starting from scratch? Start with the complete addressing guide.
