I know the advantages for businesses like yours to auto-save your work when creating an estimate in QuickBooks Online, @jen-greenfernstu. 

I want QuickBooks Online (QBO) to have this feature as much as you do. Thus, I strongly urge you to share your thoughts with our software engineers. They carefully examine customer feedback, especially when determining how to improve QuickBooks.

Here's how:

1. Sign in to your QuickBooks Online account.
2. Go to the Gear icon and select Feedback.
3. Type in your suggestion and click Next.

For future reference, here is an article you can refer to when converting an estimate into an invoice: Convert an estimate into an invoice in QuickBooks Online.

Let me know if you require further assistance managing estimates in QuickBooks Online. I'm here to help anytime. Have a good one.