How can to use Side Car on a iMac (27-inch, Late 2012) ?
How can to use Side Car on a iMac (27-inch, Late 2012) ?
How can to use Side Car on a iMac (27-inch, Late 2012) ?
You cannot, your iMac is too old according to Apple's system requirements in Sidecar
You may be able to use a non-Sidear method. See the last section in:
https://www.macworld.co.uk/how-to/ipad/second-display-sidecar-3633246/
How can to use Side Car on a iMac (27-inch, Late 2012) ?