It won't let me edit invoice, comes up with connect help and support

Hi, ollie. 

When we encounter unexpected situations while using QuickBooks Online (QBO), it's advised to perform some basic troubleshooting steps to determine if it's a browser issue. 

Your browser's cache saves files on your computer which enables the website to download faster on your next visit. However, it can also get outdated over time, leading to problems in accessing websites. 

We can open your QBO account on an incognito window. Doing so will prevent the browser history from being saved.   

Please refer to the following keyboard shortcuts based on your browser type:

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

If the private browsing session works, clear the browser's cache so the system can restart. This task is also possible in other supported, up-to-date browsers. Clearing the cache will reboot the system, allowing you to work with a clean slate. 

Furthermore, you can check out this article to learn more about personalizing your sales forms in QBO: Customise invoices, estimates, and sales receipts in QuickBooks Online.  

If you have further concerns about managing your invoice, drop your comment below. I'll circle back to help you. Take care always!