When you save your invoice document, remember to save it as a Word template, with a .dot file extension. (Go to File | Save As and choose Document Template (*.dot) from the Save As Type drop-down ...

Microsoft Word provides templates for invoice sheets that you customize to suit your business needs. Office features more than 100 online invoice templates that copy to a Word document.

Google Sheets is the company's cloud-based spreadsheet app that's available for Android phones, iPhones, Windows computers, ...