Invoice Cover Letter: Template and Example

An invoice cover letter is a one-page letter that travels with an invoice and explains it: which invoice is enclosed, what it covers, what supporting documents are attached and how the client should pay. You do not need one for routine billing, but for large projects, first invoices, grant claims and posted invoices it helps the right person approve the payment faster.

This guide gives you a ready-to-use invoice cover letter template, a completed example with real figures, variations for common situations and a list of mistakes to avoid.

When an invoice cover letter is worth sending

Most invoices only need a short email. A cover letter earns its place when the invoice alone does not tell the full story:

• Large or milestone invoices, where the approver needs to see what was delivered before signing off.
• The first invoice to a new client, to introduce your billing details, payment terms and contact person.
• Invoices with several enclosures, such as timesheets, delivery notes, progress photos or a statement of work reference.
• Grant, government or nonprofit funding claims, which often require a signed letter with each payment request.
• Paper invoices sent by post, where the letter acts as a covering note in the envelope.
• Invoices that differ from the quote, where you need to explain approved variations.

What to include in an invoice cover letter

Element	What to write
Letterhead	Your business name, address, phone, email and any registration or tax number. A clean business letterhead keeps this consistent.
Date	The date you send the letter, usually the same as the invoice date.
Recipient	Named contact, job title, company and address, or "Accounts Payable" if that is the instruction.
Reference line	"Re: Invoice INV-2045, Purchase Order PO-88120".
Opening paragraph	Invoice number, total due including tax, due date.
Summary paragraph	What the invoice covers in one or two sentences, plus a list of enclosures.
Payment paragraph	Accepted payment methods, reference to quote, and a contact for queries.
Sign-off	Name, title and signature if the client requires a signed letter.

Invoice cover letter template

[Your business name]
[Address] | [Phone] | [Email] | [Tax or registration number]

[Date]

[Contact name]
[Job title]
[Client company]
[Address]

Re: Invoice [number] for [project or period] | PO [number]

Dear [Name],

Please find enclosed invoice [number], dated [date], for [currency and total], including [tax type and amount if applicable]. Payment is due by [due date] in line with our agreed [payment terms].

This invoice covers [brief description of work, goods or period]. For your review, we have enclosed [list of supporting documents].

Payment can be made by [methods]. Please quote [invoice number] as the payment reference. If you have any questions about this invoice, contact [name] at [email or phone].

Thank you for your business.

Yours sincerely,
[Signature]
[Name, title]

Enclosures: [number] (Invoice [number]; [document]; [document])

Filled-in invoice cover letter example

Here is the template completed for a landscaping contractor billing the second stage of a commercial job.

Greenline Landscapes Ltd, 14 Mill Road, Leeds LS2 7AB | 0113 555 0142 | accounts@greenline.example | VAT No. GB 123 4567 89

12 November 2026

Ms Rachel Owen
Facilities Manager
Northgate Business Park Ltd
1 Northgate Way, Leeds LS9 4QP

Re: Invoice GL-2045 for Stage 2 planting works | PO NG-88120

Dear Ms Owen,

Please find enclosed invoice GL-2045, dated 12 November 2026, for GBP 8,640.00, including VAT of GBP 1,440.00. Payment is due by 12 December 2026 in line with our agreed 30-day terms.

This invoice covers Stage 2 of the landscaping contract: planting of the east car park beds and installation of irrigation, completed on 7 November. For your review, we have enclosed the signed completion sheet and a photo report of the finished beds.

Payment can be made by bank transfer to the account shown on the invoice. Please quote GL-2045 as the reference. For any questions, contact me at accounts@greenline.example.

Yours sincerely,
Daniel Price, Finance Manager

Enclosures: 3 (Invoice GL-2045; Stage 2 completion sheet; Photo report)

The invoice behind the letter

Line	Qty	Rate (GBP)	Amount (GBP)
Shrub and perennial planting, east beds	1	4,200.00	4,200.00
Drip irrigation supply and install	1	2,400.00	2,400.00
Mulch, 18 bulk bags	18	33.33	600.00
Subtotal			7,200.00
VAT at 20%			1,440.00
Total due			8,640.00

The check: 4,200 + 2,400 + 600 = 7,200; 7,200 x 0.20 = 1,440; 7,200 + 1,440 = 8,640. Those are the same figures quoted in the letter, which is exactly what the approver will verify. Note that for UK VAT-registered suppliers, HMRC says you normally must issue a VAT invoice within 30 days of the date of supply (VAT Notice 700/21, section 3.1), so do not hold the invoice back while you polish the letter.

How to write an invoice cover letter in six steps

1. Create the invoice first, with final totals. You can build it in our online invoice generator and export the PDF.
2. Find the right recipient. Check the contract or purchase order for a billing contact or invoice address.
3. Write the reference line with invoice number and PO number so the letter can be filed even if separated.
4. Open with the money: total, tax and due date in the first two sentences.
5. List enclosures, numbered, and make sure every listed document is actually attached.
6. Proofread figures against the invoice, then send both as PDFs or print and post them together.

Short variations for common situations

First invoice to a new client

"As this is our first invoice to Northgate, I have also enclosed our bank details on letterhead and our completed supplier form. Future invoices will follow the same format and will be sent to accounts@northgate.example unless you prefer another address."

Invoice that differs from the quote

"The total is GBP 480.00 higher than quote Q-311 because of the additional drainage work approved by email on 28 October (variation V-02, enclosed). All other items match the quote."

Grant or funding claim

"This invoice is submitted as claim 3 of 4 under grant agreement GA-2026-114 and covers expenditure from 1 July to 30 September 2026. I certify that the costs claimed were incurred for the funded project and are supported by the enclosed expenditure schedule."

Cover email instead of a letter

If the client is happy with email, condense the letter into the email body. Our examples of "please find attached invoice" wording cover that shorter format, and how to send an invoice explains delivery options.

Cover letter, invoice email or statement: which do you need?

Document	Purpose	When to use it
Invoice email	Delivers one invoice with key facts in a few lines	Routine and repeat billing
Invoice cover letter	Formally introduces an invoice and its supporting documents	Large, first, posted or grant invoices
Statement of account	Summarises all invoices, payments and the balance over a period	Monthly, or when several invoices are open
Past due letter	Formally requests payment of an overdue invoice	After reminders have failed

The cover letter is the only one of these that explains rather than asks. If you notice yourself writing "this invoice is now overdue" in a cover letter, you have the wrong document.

Formatting tips

• Use the same branding as the invoice: logo, font and colours, so both look like one package.
• Keep it to one page with generous margins; three short paragraphs are usually enough.
• Combine into one PDF when emailing, with the letter first, then the invoice, then enclosures in the order listed. Name the file with the invoice number.
• Sign it if the client or funder requires a signature; a scanned signature is usually accepted on emailed letters, but check grant terms.
• Date it the same day you send it, not the day you drafted it.
• Print on the same paper size as the invoice when posting, A4 in most countries and Letter in the US and Canada.

Mistakes to avoid

• Putting new charges in the letter. Every amount owed must appear on the invoice itself.
• Figures that do not match. A one-digit difference between letter and invoice will hold up approval.
• Writing a sales pitch. The approver wants facts; save upsells for another conversation.
• Listing enclosures that are not attached, which prompts a query email and delays payment.
• Forgetting the payment reference, which makes it harder to match the payment when it arrives. A remittance advice from the client helps, but a clear reference is simpler.
• Using a cover letter as a reminder. If an invoice is already late, send a past due invoice letter instead, which has a different purpose and tone.

The invoice still does the heavy lifting. Make it in our invoice generator without creating an account, download the PDF, and pair it with the cover letter template above.