Payouts Approval API is not available by default. Contact support to get this feature activated on your account. To use the Approvals APIs, it is mandatory to be a Technology Partner and integrate with OAuth. Only then you can make payouts.
Fork the Razorpay Postman Public Workspace and try the Payouts Approval APIs using your Test API Keys.
Approve Payouts
POST /v1/payouts/:id/approveApproves the Payout.Reject Payouts
POST /v1/payouts/:id/rejectRejects the Payout.