Good day, hello. Your correct invoices can be edited and saved, and I'm here to help rectify this problem.
 

Before anything else, may I know if you encounter an error message during the freezes? Please share the details so we can find an accurate fix.
 

For now, let's start accessing your QuickBooks Online account in a private window to address potential browser issues that affect the system's functionality. You can use these shortcut keys to access them:
 

• Safari 11 or newer: ⌘+ Shift + N
• Chrome: Ctrl + Shift + N
• Firefox: Ctrl + Shift + P
• Safari: Command + Shift + N

After you can log in using a private browser, switch back to your regular browser and clear the cache. You can also use another supported browser as an alternative.
 

Once fixed and you're ready to process payments, please refer to this article for guidance: Record invoice payments in QuickBooks Online.
 

Don't hesitate to ask help to the Community if you have any other questions or need further assistance. We're always here to help as much as we can.