Please help me to understand what does RI means in invoice numbering e.g. "RI-1001". I generated one invoice and to that invoice Quickbooks allotted number "RI-1001"

Welcome to Community, @mehul-damania.

I have an idea why your invoice numbering starts with "RI-1001". Someone must have enabled the custom transaction number of your invoice template and uses that type of invoice number. You can let QuickBooks generate the number for you or enter your desired invoice number. Let's go to your invoice template to see it.

To remove the custom transaction number:

1. Go to the Gear icon at the top, then select Custom form styles.
2. Edit your invoice template or your Standard template.
3. Tap the Content tab, and then Pencil icon on the invoice header.
4. Under the Form section, unchecked the Use custom transaction numbers box.
5. Click Done.

However, if still want to use the custom invoice number field and just want to remove the "RI" before it, you can clear the field to generate a new number. Need more details? Check out this guide: Customise invoices, estimates, and sales receipts in QuickBooks Online.

I've added these screenshots below for your reference.

 In case you need help with other customer tasks, click this link to go to our general topics with articles.

Let me know if you have questions or concerns. I'll be around to assist you. Take care and have a great weekend.