Currently, it isn't possible to run two number ranges at the same time in QuickBooks Online (QBO), rpeel. I'll elaborate on more details about this below.
In QuickBooks, you can use the Custom transaction numbers feature to set your own numbering preferences. If you utilise numbers to track your invoices, keep the option on. However, if you disable it for importing purposes, the system will automatically assign numbers to sales forms based on the last recorded figure.
Please check out this article to learn more about importing invoices to QBO: Import multiple invoices at once in QuickBooks Online.
Additionally, once your customer pays your invoice, record that transaction to balance your income and sales accounts. For a complete guide on how to do this, you can refer to this article: Record invoice payments in QuickBooks Online.
Please know that I'm always ready to back you up if you need more help customizing and managing invoices in QBO. I'll keep the thread open so you can comment back.
