Open your campaign and go to Rewards → Reward Rules.
Select New reward, or open an existing rule and choose Edit Reward.
In Step 1, select Referrer and Fixed Monetary Value.
In Step 2, choose the reward trigger. Qualified is the default option in the current editor. Set the currency and amount, such as USD 50, then choose whether the reward is one-time or ongoing.
In Step 3, under Choose Issuing Method, select Stripe Credits. The current UI labels this option Test Mode.
Give the reward a clear name. Review Auto Issue Rewards before you activate the rule.
The current Step 3 also includes Ignore Rewards for Existing Users and Reward Limit. A Retry Failed Rewards setting was visible when Stripe Credits was selected during research. Because the rule was not activated, the exact retry timing and behaviour were not tested.