Red voice recording symbol in iMessage prevents keyboard entry on MacBook Air

iMessage text box shows red lines (used to be a microphone ) and will not let me use keyboard to write text. how do i get back to keyboard entry ?

[Re-Titled by Moderator]

Original Title: iMessage Red Voice Recording Symbol Won’t Leave and on MacBook Air there is no microphone button on the keyboard. How do i get back to keyboard entry in iMessage ?