How can I match an estimate to an invoice if I forgot to create the invoice from the quotation?

Hello steve-stonecutte,

It's good to make sure you're recording your transactions the right way and I'll be glad to assist. QuickBooks Online makes it simple to manage your transactions using the amazing features offered by the program. I'd be glad to steer you in the right direction so you can focus on the things you enjoy doing. 

It's important to note that the transactions you're matching have to have the same amounts. I highly encourage you to check out this helpful article which shows you how to properly: Categorize and match online bank transactions in QuickBooks Online. The article provides the info you need in order to accurately match your transactions. 

If you still have questions, feel free to leave a comment below. I'll be here to assist.