To start a formal legal letter, place a header block at the top of the page containing your contact information, the date you send it, the recipient’s full name and address, and a reference line identifying the matter. Follow that with a formal salutation ending in a colon, then an opening paragraph that states directly why you are writing, what you want, and by when. Each of these pieces does specific work: the header creates a paper trail, the date fixes a timeline, and the opening paragraph sets the legal stakes.
Decide What the Letter Is For Before You Start
The biggest mistake people make with legal letters is drafting before they know exactly what the letter is supposed to accomplish. A demand letter for $12,000 in unpaid invoices needs a different tone, structure, and level of detail than a notice terminating a contract or a letter preserving your rights in an insurance claim. Answer one question first: what do you want the recipient to do after reading this?
That answer shapes the opening. If you want payment, you need a specific dollar amount, a deadline, and a clear statement of what happens if the recipient ignores you. If you are giving notice of a breach, you need to identify the contract, the specific provision violated, and any cure period. If you are responding to a legal threat, you need to address each claim without conceding anything you do not intend to concede. Vague letters get vague responses, or no response at all.
Build the Header Block
The top of a legal letter follows a standard block format for a practical reason: it identifies who is writing, who is receiving, and when. Skip or botch any of these elements and the letter risks being dismissed, misrouted, or unusable as evidence later.
Your Contact Information
If you are writing on letterhead, the letterhead handles this. Otherwise, place your full name, mailing address, phone number, and email address at the top left of the page. Lawyers sometimes omit their name from the header because it appears again in the signature block, but if you are writing as a private individual, put it up top so the recipient immediately sees who they are dealing with.
The Date
Place the date one line below your contact information. Use the date you actually send the letter, not the date you started drafting it. Legal deadlines, statute of limitations calculations, and contractual notice periods often hinge on when a letter was sent. A wrong date can create confusion about whether you met a deadline.
Recipient Information
Below the date, include the recipient’s full name with appropriate title, their position or role if applicable, their organization, and their complete mailing address. Verify that this information is current. A letter addressed to the wrong person or an old address gives the other side an easy argument that they never received proper notice.
The Reference Line
A reference line goes between the recipient’s address and the salutation, typically beginning with “Re:” followed by a concise description of the matter. This is where you put case numbers, claim numbers, contract dates, account numbers, or anything else that helps the recipient locate the relevant file. For example: “Re: Invoice #4892 — Outstanding Balance of $8,400” or “Re: Smith v. Johnson, Case No. 2026-CV-03421.” Be specific. A generic reference line like “Re: Legal Matter” tells the recipient nothing useful.
Use a Formal Salutation
“Dear Mr. Chen:” or “Dear Ms. Rodriguez:” is almost always the right call. Use a colon after the name, not a comma; colons signal formal correspondence. If you genuinely cannot identify the appropriate person, “Dear Sir or Madam:” works, though it is worth a phone call to get an actual name. “To Whom It May Concern” is a last resort, signaling you did not bother finding out who handles the matter, which undercuts the seriousness of the letter.
When writing to a company or government agency without a named contact, address the letter to the relevant department or office by title. “Dear Claims Manager:” or “Dear Office of the General Counsel:” is far better than a generic greeting.
Write a Direct Opening Paragraph
The first paragraph of the body does the heavy lifting. After a few sentences, the reader should know exactly what the letter is about, what you want, and why it matters. There is no place here for pleasantries, background history, or gradual buildup.
A demand letter might open: “I am writing to demand payment of $14,200 for services rendered under our agreement dated March 15, 2025, which remains unpaid despite two prior invoices.” A notice letter might start: “This letter constitutes formal notice that I am terminating our lease agreement effective June 30, 2026, in accordance with Section 12 of the agreement.” Both examples tell the recipient what is happening and anchor the claim to specific facts: a dollar amount, a date, a contract provision.
State the Deadline Up Front
If the letter requires a response or action, state the deadline in the opening paragraph or immediately after. There is no legally mandated response time for most demand letters; they are part of negotiation, not court orders. A specific date creates urgency and establishes a clear record. Fourteen to thirty days is a common range depending on complexity. Write the actual calendar date rather than a number of days: “Please remit payment by July 15, 2026” is clearer and harder to dispute than “within 30 days.”
Reference Prior Communications Briefly
If the letter connects to earlier correspondence or conversations, mention them in the opening. Something like “Following our phone conversation on April 3 and my email of April 10, both of which went unanswered…” provides context and documents a pattern without getting bogged down in narrative. Keep it to one or two sentences. Detailed history belongs in the body, not the opening.
Set the Tone From the First Sentence
Legal letters live in a narrow band between pushover and bully, and most people writing their own drift toward one extreme. The effective approach is calm authority: state the facts, state what you want, state the consequences, and let the weight of the situation do the work.
Threatening language almost always backfires. Writing “I will destroy you in court” sounds emotional and undermines your credibility. Writing “If payment is not received by July 15, I intend to pursue all available legal remedies, including filing suit in the appropriate court” says the same thing while sounding like someone who follows through. The more heated the dispute, the more important it is to keep the temperature of your language low. Judges and opposing counsel notice restraint, and they notice its absence.
Avoid sarcasm, personal attacks, and anything you would not want read aloud in a courtroom. Every legal letter you send could eventually become an exhibit. Draft the opening accordingly.
Add a Protective Marking at the Top When It Applies
Some legal letters need protective language above the salutation, and knowing when to use these markings matters.
“Without prejudice” appears on letters where you are making a settlement offer or negotiating and do not want your words used against you later in court. The marking signals that you are trying to resolve a dispute without conceding your legal position. If you write “I’ll accept $5,000 to settle this” in a without-prejudice letter, that offer generally cannot be presented as evidence if the negotiation fails and the case goes to trial. If your letter is not part of a genuine settlement negotiation, do not use this marking; courts look at the substance of the communication, not just the label.
“Privileged and confidential” applies when a communication involves legal advice between an attorney and client. Stamping the phrase on a letter does not make it privileged; the content and the relationship between sender and recipient determine whether privilege actually applies. Overusing the marking on routine correspondence dilutes its effectiveness when you need it most.
Once the header, salutation, and opening paragraph are in place, the letter has started properly, and the rest of the body can build on that foundation without having to fix mistakes made at the top of the page.