Hello there, @georgeguevara41.

In QuickBooks Online, you can create a sub-customer for a job estimate. Then, include the item in the transaction. 

Step 1: Create a sub-customer.

1. Go to the Sales menu.
2. Within the Customers tab, scroll to the customer you are preparing the Estimate for. (If your customer was not yet set up, click on New Customer at the top right of the Invoice screen to set up your customer. 
3. Tick the Is sub-customer box. Then, select the name of the customer you want to associate it.
4. Click Save.
   

Step 2: Create Estimate.

1. Go to the +New button.
2. Select Estimate.
3. Complete Estimate form with the date, product/service, description, quantity, rate, etc.
4. Click Save or Save and send to email Estimate.

If you want to learn more about converting an estimate into an invoice, you can check this article. How to convert an estimate/quote into an invoice.

Let me know if you have other questions about QuickBooks transactions. I'd be glad to help you. Take care and stay safe.