Can someone tell me why the format of my form numbers on estimates form 4 numbers to K1?

Hi there, seaward. 

I'm here to provide some insight on why the estimate number format has changed. Ideally, the number format won't automatically change unless someone has altered it. To change it back to its original format, you can do it by manually entering the correct number in the Estimate no. field. To do so, here's how:

1. Go to + New. 
2. Select Estimates.
3. Locate the Estimate no. field on the right corner of your screen.
4. Enter the correct number format. 
5. Click Save and close.

Additionally, QuickBooks will automatically remember the format or sequence you used for that transaction. That's why you don't have to worry about entering it correctly next time.

You can check this article: Customise invoices, estimates, and sales receipts in QuickBooks Online. It contains details on how you can personalize your sales forms.

Please don't hesitate to reply to this post if you have further question about modifying your estimate number format. We're always here to assist you.