The toggle function determines how a message is recorded. When toggle is enabled, the PTT button is pressed twice to record a message: once at the beginning to start the recording, and once at the end to stop the recording. The user does not need to hold the PTT button while speaking. 

This differs from the PTT’s default setting–hold to talk–which requires users to press and hold the PTT button while speaking to record your message. 

For more information on settings, check out the iOS and Android settings guides.