Invoice: when you need a signature and what to include
An invoice is a document requesting payment for goods or services delivered. Most invoices don't need a signature: they're simply sent and paid. But in some situations, a signed invoice serves as a receipt of delivery, a purchase order acknowledgment, or a formal acceptance of services. Knowing when you need one matters.
Invoice
When to use a Invoice
- When a client requires a signed invoice as proof of delivery or acceptance of services
- Government and enterprise contracts that require formal invoice acknowledgment
- Milestone invoices where you need the client to confirm deliverables were received
- International transactions where a signed commercial invoice is required for customs
Key terms in a invoice
These clauses appear in most invoice documents. Knowing what they mean helps you review faster.
Invoice number
A unique identifier for your records and the client's accounts payable. Sequential numbering (INV-001, INV-002) is standard. Some clients require their own PO number on your invoice.
Payment terms
When payment is due. 'Net 30' means 30 days from invoice date. 'Due on receipt' means immediately. '2/10 net 30' means a 2% discount if paid within 10 days, otherwise due in 30.
Itemized services/goods
A line-by-line breakdown of what you're charging for. Itemization prevents disputes and makes expense coding easier for the client's accounting team.
Late payment clause
The interest or fee applied to overdue balances. 1.5% per month is common. Check whether your client's industry or jurisdiction caps late fees.
Sign a Invoice with InkRobin
Upload your invoice, place a signature field, and send a link. The recipient signs in their browser. No account, no app. Free for up to 5 documents per month.
Questions
- Do invoices need to be signed?
- Most don't. A signed invoice is typically requested when a client needs to formally acknowledge delivery of goods or services, or when a contract or PO requires it.
- Can I use InkRobin for invoice signing?
- Yes. Upload a PDF invoice, add a signature field, and send a link to your client. They sign in their browser with no account required. You get the signed copy and an audit trail.
- What's the difference between an invoice and a receipt?
- An invoice requests payment before or after delivery. A receipt confirms payment was received. Invoices precede payment; receipts follow it.
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