I have just spent 3 hours creating an invoice and when i tried to save it as a draft it didnt save!!

You may be experiencing some browser-related issues, usermitchellprofessi.

We can sort this out by performing the basic troubleshooting steps. 

Let's start by saving an invoice on an incognito window. You can use these keyboard shortcut to open one: 

• Google Chrome: Ctrl + Shift + N
• Mozilla Firefox: Ctrl + Shift + P
• Microsoft Edge: Ctrl + Shift + P
• Safari: Command + Shift + N

If it works, you can go back to a regular browser and clear its cache. A piled cache can also be the reason for some unexpected issues on the opened pages.

You can also switch to a different supported browser like Google Chrome, Mozilla Firefox, Safari, or Microsoft Edge as alternatives.

Also, if you want to take and process payments online, you can check this reference: Take and process payments with QuickBooks Payments.

I'll be around if there's anything that I can help. Keep safe!