Hi ACke,

Thanks for posting in the Community! 

There are two ways on how you can check if a purchase order is sent or not to a supplier. 

Option 1: View purchase order in Expenses tab

1. Go to Expenses.
2. Click on Filter drop-down menu. 
3. On Type, select Purchase order. You can also change the date and status on your preference. 
4. Select Apply. 
5. You can check on the Last delivered column when the purchase order was sent. 

Option 2: Run and customise Transaction List by Supplier report

1. Go to Reports tab and search for Transaction List by Supplier.
2. Click Customise. 
3. Click on Change columns link and then tick Sent. 
4. Next, click Filter. 
5. On Transaction Type drop-down menu, select Purchase Order. 
6. Select Run report. 

Feel free to drop a comment below if you need further assistance and I'd be glad to help. Have a great day!