“Punch/Copy Paste” is not included in any official version of Audacity. It’s an optional extra.
It is actually two Nyquist plug-ins; PunchCopy.ny and PunchPaste.ny
It can be downloaded here: Punch Copy/Paste
Installation instructions for Nyquist plug-in for macOS: https://manual.audacityteam.org/man/installing_effect_generator_and_analyzer_plug_ins_on_mac_os_x.html#nyquist_install