Can you change the “estimate” to quotation instead?

Yes, you can change it, Info581. We'll just have to edit the form name.

I'll show you how:

1. Click the Gear icon.
2. Choose Custom Form Styles.
3. Look for the estimate template, then click Edit.
4. Go to the Content tab, then click the Pencil icon in the 1st row of the template.
5. Under Form names, enter the desired name of the estimate.
6. Click Done.

I'll attach screenshots to guide you:

I'd like to add the article on you can customise your invoices, estimates, and sales receipts in QuickBooks Online for future reference. 

Don't hesitate to reach out to us if ever you have other questions.