Can someone help me with my invoice numbers? They used to be sequential but now seem to be copying numbers from my Shopify integration?

Hello there. I can help you with sequencing your invoice numbers.

We can check the settings between your Shopify integration and your invoicing system for any numbering conflicts. 

Also, let's make sure to turn on the Custom transaction numbers so you'll be able to modify your invoice numbers. Once turned off, QuickBooks will automatically assign based on the last transaction number.

Here's how: 

1. Open your QuickBooks Online (QBO) account.
2. Go to the Gear icon.
3. Select Account and settings, then go to Sales. 
4. In the Sales from content option, toggle the Custom transaction numbers on.
5. Once done, click Save. 

Moreover, since Shopify integrates QuickBooks, that is the potential cause why you'll see transactions with the same number from the data provided by them. That said, QuickBooks relies on the data provided by Shopify.

Additionally, you'll want to check this article and learn how to personalise and add specific info to your sales forms: Customise invoices, estimates, and sales receipts in QuickBooks Online.

Feel at ease to reply in the comments if you need further assistance managing your invoice transaction numbers. I'd be happy to assist. Have a great day ahead of you.