If you have multiple commissions for the same goal, or are using a calculation that you want to clarify, you can use the Commission detail field to add a short descriptive note. This helps distinguish similar commissions or make the purpose of a formula clear at a glance.
The Commission detail appears directly in the commission table, so it should be concise, ideally just a few words.
You might also want to check out the Display amount feature, which can simplify how the payout value itself is shown.