Google sheets have invoice templates, so do cloud based accounting systems such as Quickbooks or Xero. You want all your invoices to have the same format and look professional. Ensure you include the following:
Your businesses contact and billing address.
You clients billing address.
Invoice number. These need to be sequential and are essential to keep things organised as they refer to that invoice alone.
Date you issued the invoice. This should be as soon after the goods or services are provided as possible.
Due date of the payment.
In a table you should have a further breakdown of what the services/goods purchased with individual prices. This can be the flat or hourly rate charged. Also have a column for quantity purchased.
Tax should be stated separately. Please see VAT section below for more details.
Payment terms. This is the amount of time you have previously agreed with the client they have to pay the invoice. It’s usually stated as ‘Net – number’. For example, if you’re client has 30 days to pay the invoice the payment terms will be ‘Net 30’.
Personal note. Add a thank you and any other information that you think would be useful for the client.