Business Documents Used With Invoices

What are business documents?

Business documents are records used to explain, approve, confirm, or organise commercial transactions. They help businesses and customers understand what has been agreed, what has been supplied, how much is owed, and whether payment has been completed.

Some documents are created before work begins, while others are issued after goods or services have been delivered. An invoice is normally used to request payment, but it may be supported by several other documents depending on the transaction.

Why invoices are often supported by other documents

An invoice shows the amount a customer must pay, but it may not contain every detail connected to the original agreement or completed work.

Supporting documents can provide additional evidence about:

• what the customer requested
• what goods were delivered
• how many hours were worked
• whether the customer approved the purchase
• which invoices remain unpaid
• when a payment was sent

How business documents reduce confusion

Using clear business documents can reduce misunderstandings between the seller and the customer. Each document has a different purpose, making it easier to follow the transaction from the initial request through to final payment.

For example, a quote may show the proposed price, a purchase order may confirm the customer has approved the purchase, a delivery note may confirm that goods arrived, and the invoice may request payment.

Documents used before an invoice

Several documents may be created before an invoice is issued. These documents help define the work, pricing, and responsibilities of each party.

Common documents used before invoicing include:

• quotes
• estimates
• contracts
• purchase orders
• work orders

Quotes and estimates

Quotes and estimates are normally provided before work begins. A quote usually presents a fixed proposed price for a specific product or service, while an estimate gives an approximate cost that may change as the work progresses.

Once the customer accepts the price and the work is completed, the business can issue an invoice requesting payment.

Purchase orders

A purchase order is normally created by the customer and sent to the supplier. It confirms which goods or services the customer wants to purchase and may include quantities, prices, delivery details, and a purchase order number.

The supplier can include the purchase order number on the invoice so the customer can match the invoice to the approved purchase.

What is a delivery note?

A delivery note is a document that accompanies goods when they are delivered to a customer. It normally lists the products and quantities included in the delivery.

Unlike an invoice, a delivery note does not usually request payment. Its main purpose is to confirm that the correct goods were delivered.

The customer may sign the delivery note to confirm that the delivery was received. The supplier can then use the signed document as supporting evidence if there is later a disagreement about missing or damaged goods.

Invoice vs delivery note

An invoice and a delivery note may contain similar information, but they serve different purposes.

A delivery note confirms what was physically delivered, while an invoice explains how much the customer must pay. A business may send both documents as part of the same transaction.

• A delivery note confirms delivery
• An invoice requests payment
• A delivery note may be signed by the customer
• An invoice includes prices, totals, and payment terms
• A delivery note may not show item prices

What is a timesheet?

A timesheet records the amount of time spent completing work. Timesheets are commonly used by freelancers, consultants, contractors, tradespeople, agencies, and other businesses that charge customers by the hour.

A timesheet may include the date worked, number of hours, task completed, project name, and hourly rate.

Should you attach timesheets to an invoice?

Businesses that invoice for hourly work may choose to attach a timesheet to the invoice. This helps the customer understand how the total number of billable hours was calculated.

Providing a timesheet can also reduce disputes because the customer can compare the invoice with the work completed during the billing period.

The invoice should still contain clear line items. The timesheet acts as supporting evidence rather than replacing the invoice.

What is an account statement?

An account statement provides a summary of transactions between a business and a customer over a particular period. It may show invoices issued, payments received, credit notes, refunds, and outstanding balances.

Statements are particularly useful when a customer has several invoices with the same business.

Invoice vs statement

An invoice requests payment for a specific transaction. A statement provides a wider summary of activity on the customer's account.

For example, a customer may receive four separate invoices during one month. At the end of the month, the business could send an account statement showing all four invoices, any payments already made, and the remaining amount owed.

• Invoices relate to individual transactions
• Statements summarise multiple transactions
• Invoices include payment terms and line items
• Statements show account activity and balances
• A statement does not normally replace an invoice

What is remittance advice?

Remittance advice is a document sent by a customer to confirm that an invoice payment has been made. It may include the invoice number, payment date, amount paid, payment method, and customer details.

Businesses can use remittance advice to match incoming payments with the correct invoices, especially when one payment covers several invoices.

Is remittance advice proof of payment?

Remittance advice shows that the customer says a payment has been sent, but the business should still check its bank account or chosen payment method to confirm that the money has arrived.

It is useful for payment matching and record keeping, but it should not automatically be treated as confirmation that the payment has cleared.

Other documents used with invoices

Depending on the business and transaction, an invoice may also be supported by:

• contracts
• receipts
• credit notes
• expense records
• work completion certificates
• project reports
• signed approval forms
• proof of postage or delivery

How to reference supporting documents on an invoice

Businesses should make it easy for customers to connect an invoice with the related transaction. Relevant reference numbers can be included in the invoice details, notes, or line item descriptions.

Useful references may include:

• purchase order number
• quote number
• project number
• contract reference
• delivery note number
• timesheet period
• customer account number

Keep document information consistent

The information shown across business documents should remain consistent. Customer names, business details, item descriptions, quantities, dates, and agreed prices should match wherever possible.

Differences between a quote, purchase order, delivery note, and invoice can cause delays because the customer may need to investigate the transaction before approving payment.

How to organise invoice documents

Businesses should keep related documents together so they can be found easily when a customer asks a question or disputes a charge.

Documents can be organised using folders named after customers, projects, months, or invoice numbers. A consistent file naming system also makes it easier to locate records.

• INV-2026-001-Invoice.pdf
• INV-2026-001-Timesheet.pdf
• INV-2026-001-Delivery-Note.pdf
• INV-2026-001-Remittance.pdf

Creating a clear invoice

Even when supporting documents are provided, the invoice itself should remain clear and complete. Customers should not need to search through several attachments just to understand the amount they owe.

A professional invoice should clearly show the seller and customer details, invoice number, invoice date, payment due date, descriptions, quantities, rates, taxes, discounts, additional charges, and total balance due.

Use InvoiceAtlas to create your invoice

InvoiceAtlas allows businesses, freelancers, and contractors to create professional invoices directly in their browser.

You can enter your business information, customer details, invoice items, taxes, discounts, notes, and payment terms before downloading the completed invoice as a PDF.

Supporting documents such as timesheets, delivery notes, and purchase orders can then be stored alongside the invoice to maintain a clear record of the transaction.