--- title: Mail an invoice online description: Most invoices go by email. But sometimes paper is necessary—when a client requires it, when you need a dated delivery record, or when you're documenting a collections effort. seo-description: Mail a paper invoice when email isn't enough. Learn when physical invoices are necessary, what to include, and how to create a paper trail for collections. group: use-cases indexable: true schema: software eyebrow: Business published: 2026-01-19T15:44:02-06:00 updated: 2026-01-19T23:53:33-06:00 path: /mail-invoice-online cta-label: Build my invoice mailing packet cta-href: /forms/payment-demand-packets?lane_friendly_reminder=true cta-note: Upload your invoice PDF and we'll print and mail it for you. cta-action: link --- # Mail an invoice online Most invoices go by email. But sometimes paper is necessary—when a client requires it, when you need a dated delivery record, or when you're documenting a collections effort. ## Pricing Pricing is based on page count. You see the total before checkout. See pricing ## When to mail a paper invoice **Client requirement** — Some businesses, government agencies, and older organizations only process paper invoices. If they've told you "mail it," mail it. [Mail my invoice](cta) **Proof of delivery** — When you need documentation that the invoice was sent and received, mailed invoices with Certified Mail create a paper trail that email can't match. **Collections escalation** — If you're moving toward formal collection efforts, mailed invoices and notices create evidence that you properly billed the customer. **Contract requirement** — Some contracts specify that invoices must be sent by mail to a particular address. If the client accepts email and you don't need proof of delivery, email is faster and cheaper. ## What to include on an invoice A complete invoice should have: **Your information** - Business name and address - Contact information (phone, email) - Tax ID or business registration number (if applicable) **Client information** - Company or individual name - Billing address - Account number (if you assign one) **Invoice details** - Invoice number (unique, sequential) - Invoice date - Due date (be specific: "Due January 31, 2026" not "Net 30") - Purchase order number (if the client provided one) **Line items** - Description of goods/services - Quantity - Unit price - Line total **Totals** - Subtotal - Tax (if applicable) - Total due - Amount already paid (if partial payment received) - Balance due **Payment instructions** - Accepted payment methods - Where to send payment (address for checks, link for online payment) - Bank details for wire transfer (if applicable) ## Invoice mailing best practices **Send invoices promptly** — Mail invoices within a few days of completing work or delivering goods. Delays create cash flow problems. **Keep copies** — Keep a copy of every invoice you send. If you end up in collections or court, you'll need it. **Match addresses** — Use the billing address the client provided. If you're not sure, confirm before mailing. **Include a return envelope** — For clients who pay by check, a return envelope (pre-addressed, not necessarily pre-stamped) increases the chance of timely payment. **Number invoices sequentially** — Makes tracking easier and looks professional. Gaps in numbering can look suspicious if records are audited. ## When an invoice is past due If an invoice goes unpaid, escalate with increasingly formal notices: **First reminder (7–14 days past due)** A friendly note: "This invoice is past due. Please remit payment or contact us if there's an issue." **Second notice (30 days past due)** More direct: "Your account is 30 days past due. Please pay immediately to avoid further action." **Final demand (60+ days past due)** Formal final notice before collections or legal action. [Learn about final demand letters](/final-demand-letter) Each notice creates evidence of your collection efforts. ## Using Certified Mail for invoices For most routine invoices, regular First Class mail is fine. Use Certified Mail when: - You're sending a past-due notice - You need proof the invoice was delivered (for dispute purposes) - You're building a paper trail for potential collections - The client has claimed they "never received" invoices before Certified Mail with Electronic Return Receipt provides tracking and signature confirmation. ## How to mail an invoice with PostalForm 1. **Export your invoice as PDF** — From QuickBooks, FreshBooks, Excel, or any invoicing software 2. **Upload to PostalForm** — We show a preview 3. **Enter addresses** — Your business address and the client's billing address 4. **Choose delivery options** — First Class for routine invoices, Certified Mail for past-due notices 5. **Checkout** — We print and mail through the appropriate mailing provider ## Tips for invoice cover letters For significant invoices or new clients, consider adding a brief cover letter: ``` [Date] Dear [Client Name], Please find enclosed Invoice #[number] for $[amount], due [date]. If you have any questions about this invoice, please contact me at [phone/email]. Thank you for your business. Sincerely, [Your name] ``` The cover letter goes first in the PDF, invoice pages follow. ## Related - [Payment Demand Packets](/forms/payment-demand-packets) - [Mail a final demand letter](/final-demand-letter) - [Mail a past due notice letter](/past-due-notice-letter) - [Payment demand letter template for services rendered](/letters/payment-demand-letter-template) - [Certified Mail online](/certified-mail-online) - [Mail a letter online](/send-letter-online) ## Ready to send it? Upload your invoice PDF and we'll print and mail it for you. [Build my invoice mailing packet](/forms/payment-demand-packets?lane_friendly_reminder=true)