If you want to inform something to your affiliate about the payout, then you add notes to the Invoice
Step 1. Click on "Rewards" on the Dashboard
Step 2. Under "Manage Invoices", click the blue "Edit" button across a specific Affiliate
Step 3. In the next page, scroll down to see the Comments Box. First box is for internal comments for the yourself(Admin). Second box is for the Affiliate to see.
Step 4. Add your notes and click "Update"
Step 5. To view the notes, go to your affiliate's dashboard.
Step 6. On "My Rewards" section, click on View Details. And here you can view the notes that your affilaite to see.