You can make an outbound call to the SIP URI of a Plivo application you've created. For example, you can make an HTTP POST request to originate an outbound call to "sip:example@app.plivo.com," which is the SIP URI used to identify the Plivo application.
If you’re expecting to receive calls to your SIP URI, you must create a SIP endpoint that’s attached to your Plivo application by visiting Voice > Endpoints in the Plivo console. Share this endpoint, not the SIP URL of your application.