erase Mac for trade in
when I get to Transfer or reset (after transferring all data to new machine) I tried to click Erase all content and settings and I get the message "Erase Assistant Not Supported on this Mac" I tried restarting and holding down command "R" and the computer just clicked like I was holding down a key by mistake.
How do I erase all data from my old Mac?
iMac 27″, macOS 10.15