DroidCam had the most clear instructions within the app, but only works with Windows or Linux machines. I tried IP Webcam (free, or $4 for the Pro version), DroidCam (free, or $5 for the Pro version), and EpocCam Webcam (free, or $5 for the Pro version). There are dozens of free and paid apps that can help you transform your workhorse smartphone into a webcam.
Find and download the right webcam app for Android or iPhone