Adding an estimate is quite easy, louisianatouch@g.
You can create an estimate for your prospective customers and convert them into invoices thereafter.
Here's how to create an estimate:
- From your homepage, click the + New button and choose Estimate.

- On the page that appears, enter all the necessary information like the customer’s name and all the necessary information.
- Click on the Save and send button at the bottom once you’re done.
You can refer to this article for more information: Set up and use estimates.
When your customer accepts the estimate, you can now automatically turn it into an invoice, check this article for more information: Convert an estimate into an invoice in QuickBooks Online.
Let me know if there's anything that I can further assist you with creating an estimate. I'm always glad to help in any way I can.