How to Send an Invoice | Step-by-Step Guide (2026)

Knowing how to send an invoice correctly is the difference between getting paid on time and chasing money for weeks. A well-structured invoice sent through the right channel can cut your average collection time in half.

This guide walks you through every step, from building the invoice itself to choosing the best delivery method and following up when payment is late.

What to Include Before You Send an Invoice

Before you hit send, make sure your invoice contains every piece of information the client needs to pay you without asking questions. Missing details are the number-one reason invoices get delayed.

Every invoice should include:

Your business name and contact information — legal name, address, email, and phone number
Client's name and billing address — match exactly what's in their accounting system
A unique invoice number — sequential numbering helps both sides track payments
Invoice date and due date — be explicit (e.g., "Due: March 15, 2026" instead of "Net 30")
Itemized line items — description, quantity, unit price, and line total for each service or product
Total amount due — including any taxes, discounts, or fees
Accepted payment methods — bank transfer, credit card, PayPal, or online payment link
Payment terms — late fee policy, early payment discounts if applicable

If you're not sure where to start, free invoice templates give you a professional layout with all required fields already in place.

Step 1: Create Your Invoice

You have three main options for creating invoices:

Use Invoicing Software (Recommended)

Dedicated invoicing software auto-fills your business details, calculates taxes, tracks payment status, and sends reminders automatically. This is the fastest method once you've set up your account.

Use a Free Invoice Generator

If you only send a few invoices per month, a free invoice generator lets you build professional invoices without creating an account. You fill in the details, download a PDF, and send it yourself.

Build From a Template

Word or Excel templates work in a pinch, but they require manual calculations and don't track whether the client has viewed or paid the invoice. Use invoice templates as a starting point if you go this route.

Step 2: Choose Your Delivery Method

How you send the invoice matters almost as much as what's on it. The right delivery method depends on your client's preferences and how quickly you need payment.

Email (Most Common)

Email is the standard for most B2B invoicing. Attach the invoice as a PDF and include a brief, professional message in the body:

Subject line: "Invoice #1042 from [Your Business] — Due March 15"
Body: A one-sentence summary of what the invoice covers, the total, and a direct payment link
Attachment: PDF of the invoice

Pro tip: Include a payment link directly in the email body. Clients who can click and pay immediately are far more likely to pay on time than those who need to download, open, and manually process a PDF.

Shareable Payment Link

Many invoicing platforms, including Billed, generate a unique URL for each invoice. The client clicks the link, views the invoice in their browser, and pays online instantly. This method has the highest on-time payment rates because it removes friction.

Postal Mail

Some industries, government agencies, and larger corporations still require mailed invoices. If you send paper invoices:

Use company letterhead
Include a self-addressed return envelope for check payments
Mail invoices the same day you create them to avoid unnecessary delays
Consider sending via certified mail for large amounts

Client Portal

If your client uses a vendor portal or accounts payable system (like Coupa, Ariba, or Bill.com), you may need to submit invoices through their platform. Ask during onboarding so you're not scrambling later.

Step 3: Set Clear Payment Terms

Payment terms tell the client exactly when and how to pay. Vague terms lead to vague payment timelines.

The most common payment terms for small businesses:

Due on Receipt — payment expected immediately upon receiving the invoice
Net 15 — payment due within 15 days
Net 30 — payment due within 30 days (most common)
2/10 Net 30 — 2% discount if paid within 10 days, otherwise full amount due in 30

Choose terms based on your cash flow needs and industry norms. If cash flow is tight, shorter terms or upfront deposits make a significant difference. Learn more in our detailed guide on invoice payment terms.

Step 4: Send at the Right Time

Timing affects how fast you get paid. Here are guidelines backed by payment data:

Send immediately after delivering work — the value is freshest in the client's mind
Invoice on Tuesday through Thursday — invoices sent mid-week get paid faster than those sent on Friday or Monday
Send in the morning — invoices received before noon are more likely to be processed same-day
For recurring work, pick a consistent date — the 1st or 15th of each month helps clients budget

If you bill on a recurring schedule, set up recurring invoices to automate the entire process.

Step 5: Follow Up on Unpaid Invoices

Even perfectly crafted invoices sometimes go unpaid. A systematic follow-up process is essential:

Day of due date — send a friendly reminder: "Just a heads-up that Invoice #1042 is due today."
3-5 days past due — follow up by email: "I wanted to check in on the status of Invoice #1042, which was due on [date]."
14 days past due — call the client directly. Email may have been missed or buried.
30+ days past due — send a formal overdue notice with your late fee policy.

Automating payment reminders through your invoicing software eliminates the awkwardness and ensures nothing falls through the cracks. For a deeper dive, see our guide on how to follow up on unpaid invoices.

Common Mistakes That Delay Payment

Avoid these pitfalls that slow down your cash flow:

Missing or incorrect client details — if the billing contact or PO number is wrong, the invoice gets stuck in their system
No payment link — making clients manually enter bank details creates unnecessary friction
Vague descriptions — "Consulting services" doesn't help an AP department approve payment; be specific about what you delivered
Wrong currency or tax rate — double-check these for international clients
Sending to the wrong person — confirm who handles payments during onboarding, not after the invoice is overdue

How to Send an Invoice: Quick Checklist

Use this before every invoice you send:

All required fields filled in (business info, client info, line items, totals)
Invoice number is unique and sequential
Due date is clearly stated
Payment methods and links are included
PDF is attached (for email) or link is generated
Subject line includes invoice number and due date
Sent to the correct billing contact

Conclusion

Sending an invoice well means getting paid faster. Create a complete, professional invoice with all required details, deliver it through the channel your client prefers, set clear payment terms, and follow up systematically when payment is late.

Ready to streamline your invoicing? Try Billed free to create, send, and track professional invoices, with automatic payment reminders and online payment links built in.

How to Send an Invoice: A Complete Guide for Small Businesses