My invoice numbers keep randomly changing to other customers names !

We can perform some troubleshooting steps together to resolve your issue with invoice numbers in QuickBooks Online (QBO). 

If you are referring to the invoice numbers applied to other customer's names after creating an invoice, then you might be experiencing some browser issues. The system occasionally behaves strangely when the browser frequently accesses pages that could be due to corrupted cache files.

To rectify this, let's perform a few troubleshooting solutions. I suggest using a different browser or a private window. Depending on the browser you're using, you can use these keyboard shortcuts: 

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

Once done, create an invoice to see if it will not apply to another customer's name. We can also open the existing invoice and manually change the invoice number to the correct one. If it works, go back to your regular browser and clear its cache to start fresh. Also, using other supported browsers can help us narrow down the cause of this unusual behavior.

Lastly, I'm adding here some links about customizing numbers on the sales forms in QBO for reference: 

• How to change the invoice number on sales forms
• Reset your transaction numbers

I'm just one reply away if you need a hand with managing your customer's transactions in QBO. I'm always here to ensure your success. Take care always.