After finishing paying to your affiliate, both you or your affiliate can export the invoice for the paid referrals by enabling Export Invoice feature
Go to Settings => Payment => Advance: Export invoice and click On to enable that feature
After Marking referral order as paid, you can download invoice on Payment tab => Paid => See transaction details => Download invoice:
The exported invoice will contain the following information: Invoice ID, Payment method, Payment information, Payment amount, Affiliate name and Referral details
Also, your affiliate can see referral details and export invoice with the same information On Payment tab => See payment details => Download Invoice: