Can you connect Mac mini to 10 year old I MAC? (I have Mac desk top made in 2010)
Is there any chance to use the Mac Mini with this computer or does it have to be a newer model?
iMac 21.5″, macOS 10.13
Question marked as
Use your iMac as a display with target display mode - Apple Support
It will work if it's a 27"iMac. You will need a Mini DisplayPort cable, such as:
https://www.apple.com/shop/product/HN8B2ZM/A/mophie-usb-c-cable-with-mini-displayport-connector