1) In Melio, click Pay, then click the Paid tab
2) On the Paid tab, locate and click your desired payment to display the Payment activity screen
3) On the Payment activity screen you'll see a section called Vendor Received, that section will show the paper check number
TIP: if you Sync Melio with QuickBooks Online, the paper check number will appear on the BILL PAYMENT in QuickBooks Online.