New to QBO. Why use an outside app such as Jobber or Buildertrend for estimates if QBO offers it?

Do you mean this Jobber as a field service app?

https://jobber.grsm.io/quickbooks

It offers the approval feature and your client can sign your estimate. This feature is unavailable on QB. 

Hi kimwaters,

Welcome to the QuickBooks family!  QuickBooks Online is an exceptional accounting software that allows you to work anytime from anywhere.  With many built in features for all of your bookkeeping needs, creating estimates is valuable for providing proposals for the work you plan to do for your customers.  I'll be happy to provide more information!

Creating estimates within QuickBooks is a great way to keep all of your records in one place.  Once you've created an estimate, it can be easily converted to an invoice to eliminate additional entries, saving valuable time.  You'll also have the ability to update the status of the estimates when your customer has decided to accept the proposal, keeping your accounts accurate.  When an estimate is created it's not considered as a transaction until it's been accepted.  In addition, you can run an Estimates by Customer report to easily view the associated information such as the customer name, estimate number, the status and the invoice number.  Creating and sending estimates in QuickBooks Online is the way to go for tracking your work with confidence, without the need for third party apps.

If you have any other questions, please feel free to reach back out.  We'd love to help!