Affiliate commission is income, and how it is treated depends on your circumstances.
WHAT WE CAN TELL YOU
What we paid you, when, and in what form. Your payout history is in the Affiliates section.
WHAT WE CANNOT TELL YOU
How to treat it for tax purposes. That depends on your residence, your status as an individual or a business, the amounts involved and local rules. Speak to an accountant.
PRACTICAL POINTS
Keep your own record of payouts received, with dates and amounts. If you take commission as account credit rather than cash, note that too, since it may still be income in substance. If you operate as a registered business, make sure your Client Area account carries the business details.
IF YOU NEED DOCUMENTATION
Open a ticket describing what your accountant requires. We can usually provide a statement of payouts for a period.
DO NOT
Rely on assumptions about thresholds or treatment. The amounts are usually modest, but modest income is still income, and it is cheaper to ask an accountant once than to correct it later.