If someone uses Circle to request that you send them money, you will receive an email to let you know.
If you have push notifications enabled in Settings you will also receive a push notification to alert you to the request.
Send an email
Or a Push
You will also see a notification under Recent Activity upon logging into your Circle account.
Click on the link in the email or on the link in your recent activity to pay or deny the request.
The requester will be notified if you decide to deny the payment. If you choose to pay it, you'll see a final confirmation screen.