You did the work. You delivered the product. Now you need to get paid. Sending an invoice sounds simple — but the way you send it, what you put in it, and how you follow up can mean the difference between payment in 7 days and payment in 60.
This guide covers everything you need to know about sending professional invoices online: what to include, how to structure payment terms, how to handle late payers, and why switching from emailing PDF attachments to an online invoicing platform dramatically accelerates cash collection.
What should a professional invoice include?
A legally sound, professional invoice needs these elements:
- Your business name, address, and contact details — including your business registration number if applicable in your jurisdiction
- The client's full name and billing address
- A unique invoice number — sequential numbering makes it easy to reference in correspondence and accounting software
- Invoice date and payment due date — be explicit; "30 days" is vague, "due by April 15, 2025" is not
- Itemised line items — description, quantity, unit price, and line total for each product or service
- Subtotal, tax, and total amount due
- Payment instructions — bank details, accepted card types, or a link to pay online
- Late payment terms — e.g. "1.5% per month on overdue balances"
Missing any of these can create disputes, delay payment, or cause compliance issues at tax time.
PDF invoices vs online invoicing: why it matters
The traditional workflow — create an invoice in Word or Excel, save as PDF, email as an attachment — has serious limitations:
- Clients have to manually initiate a bank transfer or dig out a card to pay
- You have no visibility into whether the email was opened
- Chasing payment requires separate manual follow-up emails
- Reconciling payments against invoices is a spreadsheet exercise
Online invoicing software replaces this with a client payment portal: a unique, branded link where clients can view the invoice and pay instantly by card or bank transfer. The friction of "I'll get to it later" disappears when payment is one click away.
Research from the payments industry consistently shows that invoices with a "Pay Now" button are settled an average of 8–12 days faster than PDF invoices requiring manual payment.
Choosing the right payment terms
Payment terms are a negotiation — but here are proven defaults to start with:
- Net 14 — best for small project-based work and freelancers; keeps cash flow tight
- Net 30 — the most common in B2B; balances client expectations with your cash needs
- Net 60 — appropriate only for large enterprise clients with formal procurement processes
- Due on receipt — for retainer payments, subscriptions, or clients with a history of late payment
Whatever terms you agree, enforce them consistently. Clients quickly learn which suppliers actually follow up on late invoices and which don't.
How to reduce late payments
Late payment is the single biggest cash flow killer for small businesses. These steps make a measurable difference:
- Send invoices the same day work is delivered — every day you wait is a day added to the payment clock
- Enable online payment — clients pay faster when the path of least resistance leads to a payment button
- Send a polite reminder 3 days before due date — a friendly heads-up is not aggressive; it's professional
- Follow up on the due date if unpaid — same day, not a week later
- Automate your reminder sequence — invoicing software can do this for you; you shouldn't be manually drafting chase emails
- Charge late fees — even if you rarely enforce them, stating your late payment policy on the invoice signals that you take terms seriously
What to look for in online invoicing software
Not all invoicing tools are created equal. When evaluating your options, prioritise:
- Client payment portals — clients should be able to pay online without creating an account
- Multiple payment methods — credit card, ACH/bank transfer, digital wallets
- Automated reminders — configurable reminder sequences for upcoming and overdue invoices
- ERP/accounting integration — invoices should sync back to QuickBooks, NetSuite, Xero, or whatever you use for bookkeeping
- Branded templates — your invoice should reflect your business, not your software vendor
- Aging reports — you need to see at a glance what's outstanding and how long it has been outstanding
Getting started today
The fastest way to improve your invoicing process is to stop sending PDF attachments and start sending payment links. With a platform like TallyArc, you can create a branded invoice, connect Stripe or PayPal, and send your first online invoice in under 10 minutes.
Your clients will appreciate the simpler payment experience. Your bank account will appreciate the faster collections.