Invoices used to create their own invoice number now its using an old invoice number from one of our different lotus programs

Welcome to the Community, archiesappliance.

If you want to continue the sequence, you can use the last number in your first invoice in QuickBooks Online (QBO).

By default, QuickBooks automatically follow the numbering adds +1 to the number to get the next invoice number.  Thus, QuickBooks uses the last number in your latest invoice to continue the numbering sequence.

To fix your issue where using an old invoice number is to set it up on your Accounts and Setting.

Here's how:

1. Go to the Gear icon and choose Account and Settings.
2. From the Sales tab, click the pencil icon for Sales form content.
3. Make sure to turn on the Custom transaction numbers.
   
4. Click Save, then Done.

After that, edit the invoice number and change it to the correct one. To do this, just go to Sales and choose Invoices. Then, select the transaction and manually edit the invoice number from there.

Once done, QuickBooks will remember the new invoice number and continue the sequence.

You can also check out this article to learn more about customizing templates in QBO: Customize invoices, estimates, and sales receipts in QBO.

If you want to review the invoices you made, run the Invoice List. Pull this up by going to the Reports menu at the left pane then type Invoice List on the search bar.

Visit us again if you need additional help with invoice numbers or anything about QuickBooks. It will be my pleasure to help. Stay safe and have a nice day.