Let me show you how to generate a report showing purchase orders you've created under a specific vendor in a CSV file, @Ffraga.

After creating a purchase order, you can run a Quick Report. Then, after generating the report, export it into a comma-separated values (.CSV) file.

Here's how:

1. Go to the Vendors menu and select Create Purchase Orders. 
2. Select the Reports menu between the Formatting and Search tab. 
3. Choose Quick Report. 
4. Click on Customize Report button then the Display tab to add all the Columns you need like the Date, Item, Qty, and etc.
5. Go to the Filter tab to select the Transaction Type to Purchase Order. 
6. Choose OK once done.
7. Click the Excel button at the top and choose Create new worksheet. 
8. Choose Create a comma separated values (.csv) file and click on Export button. 

Check this article on how to customize reports in QuickBooks Desktop. Also, here's how to import or export MS Excel files. 

I’ll be here if you have any additional questions about your reports, or anything else. Just drop a comment below. Enjoy your day!