You have me to help you change the form name, userengtong.

We can change it through the Custom form styles section. Let me guide you with these steps:

1. From the Gear icon, select Custom form styles.
2. Select the Estimate form.
3. Go to the Content tab.
4. Click the header.
5. Under Form, change Estimate to Quotation.
6. Click Done.

On the other hand, for us to add a custom column on the form, we'll have to import our style. This way, we can design our custom form style.

I've also added this article when you're ready to convert the estimate to an invoice: Convert An Estimate Into An Invoice in QuickBooks Online.

Feel free to get back to me if you need help. Keep safe!