What to put on an invoice so you actually get paid
Most late payments are not disputes, they are invoices that could not be processed. A payable invoice names both businesses and their addresses, carries a unique invoice number, states the date it was issued and the date it is due, breaks the work into lines a client can recognise, shows tax as its own line rather than folded into the total, and tells the client exactly how to pay — bank name, account number and any reference they need to quote.
Two things are worth the extra minute. Put the due date in words as well as a date, so "due within 14 days" and the date agree. And send it to the person who processes invoices, not only the person who hired you.
Quotation, invoice or receipt — which one to send
A quotation comes first. It is a price you are offering before any work happens, and it usually carries an expiry so the price cannot be held against you months later. Nothing is owed yet.
An invoice is a demand for payment for work already done or goods already delivered. It creates the debt, which is why it needs a number and a due date.
A receipt comes last and confirms that money has arrived. Cash and bank transfers are where receipts matter most, because there is no card statement doing the job for you.
Choosing the right tax line for your country
The arithmetic is the same everywhere; the label and the rate are not. Pakistan charges sales tax, the UK and the Gulf states charge VAT, India and Australia charge GST. Pick your country in the generator and the invoice picks up the right wording, the right rate and the right currency format.
The United States is the exception. There is no national sales tax — it is set by state and often by city — so enter the combined rate that applies where the sale takes place. The VAT calculator will take a custom rate for exactly this reason.
If you are not registered for tax, leave the tax line off entirely rather than charging 0%. An invoice showing a tax line at zero suggests you are registered and simply zero-rated, which is a different thing.