I am looking to reset invoice numbers? I customised 1 invoice number and can’t change it back to the automated way. I’d like quick books to allocate number for me. HELP!

Your issue ends here, @mike_hatch.

Allow me to fill you in on everything about assigning numbers to your sales forms in QuickBooks Online (QBO).

In QBO, when you utilise the Custom transaction numbers feature, it'll automatically assign numbers to your sales forms depending on your own numbering preference setup. In your case, since you customised the invoice number starting by 1, the next invoice numbers will automatically follow the number sequence by 2, 3, and so on for new invoices.

Also, just in case you want to automatically send reminders to customers in the future, feel free to check out this article for more guidance: Automate invoice reminders in QuickBooks Online.

I'm always here to listen if you have additional concerns with invoicing. You're welcome to post again or leave a reply below. Have a good one.