Hello Neela1,
Welcome to the QuickBooks Online family. I'll be happy to steer you in the right direction so you're on the right track.
You're welcome to use QuickBooks to administer the estimates using QuickBooks. Here's a helpful article that shows you how to: Create and send estimates in QuickBooks Online. You can also search for add-on apps on our site www.apps.com.
Feel free to check out these helpful tutorials/webinars that you can reference in order to cut the learning curve for QBO. You're more than welcome to ask other questions in the comments below. I'll be one message away.
