Every business owner should have this on hand just incase of trouble with your normal system if nothing else. It's free, it works, don't need to be a rocket scientist to use it. The same company makes a full blown accounting software that is just as great.

Trulysmall provides free customizable invoice templates for any word processor or spreadsheet format. Completely custom is an option too. Templates are organized by business type so time spent working on it can be cut even shorter if you're in a hurry.They're easy to navigate and fill but if help is needed fear not, customer service is great. Downloading/sharing is over in one click.

I consider myself to be a critical person but I don't have hardly anything to complain about here. Once I needed to reach out to customer service and they took a while to respond but they were polite and knew what they were ranking about, that's actually rare these days.