It's nice to see you here in the Community, @MIchelHMC. I'm here to guide you run a job cost report in QuickBooks Online (QBO).

To achieve this, you can simply run the Project Profitability report and filter the data. Here's how:

1. In your QBO account, select the Projects menu.
2. Next, click the project associated with the job and the vendor.
3. Once opened, go to the Project Reports tab.
4. From there, select Project Profitability.
5. Click the Customize button and set the correct date range.
6. Then, go to the Filters menu and check the box for Customer and select the job name. Tick the box for Vendor and choose the vendor's name. You can also select multiple names. 
7. When finished, select Run Report. 

For reference, check out this article: Set up and create projects in QuickBooks Online. 

I've also attached this helpful resource to help you classify the transactions to organize the info in your account: Turn on class tracking in QuickBooks Online. 

Don't hesitate to post a reply below if you have any other concerns running a job costs report. I'll be right here to assist you further. Have a good one.