Hello,
If I want to insert a record scratch noise in the audio, do you know how? What is it called?
You mean like a DJ “scratch” effect?
If so, try this Nyquist “scratch effect” plug-in (apply to a short section of the recording) http://forum.audacityteam.org/download/file.php?id=5234
Instructions for installing Nyquist plug-ins: http://audacityteam.org/download/plugins