Can I change the heading of the "estimate " to something else like "Proposal"?

Thanks for getting in touch with the Community, northmen23.

You can change an estimate template's Form name while customizing it.

Here's how:
 

1. Open an existing estimate, or begin to create a new one.
2. At the bottom, find and click your Customize option.
3. Choose Edit current.
4. Access the Content tab.
5. Hit your header section to highlight it and display the available customization options.
6. Under your Form names section, enter a term you prefer, like "Proposal", or another term, to title the template.
7. Select Done.
   
   

Now when you view PDF copies of your estimates, you'll see the term "Estimate" replaced in its normal header locations with the word you entered while customizing your estimate template.

I've also included a detailed resource about customizing forms which may come in handy moving forward: Customize invoices, estimates, & sales receipts

Please don't hesitate to send a reply if there's any additional questions. Have a great Thursday!