I have the MacBook Pro 14-inch 2021 running on Sonoma 14.2.1 and I would like to use my iMac 24-inch, 2023 as a 2nd screen for my Macbook Pro.
Can someone please provide a step by step guidance of what I need to do to be able to achieve this?
Thank you
Apple only provides Target Display Mode for this capability. Unfortunately, neither your iMac, nor your MacBook would qualify for this ... as they are too new.
Ref: Use your iMac as a display with target display mode - Apple Support
That iMac doesn't support Target Display Mode – and that MacBook Pro doesn't support using any iMac as a Target Display Mode display.
Those machines are new enough that you could set up either Mac as an AirPlay Receiver for AirPlay to Mac, and use it as a second screen for the other. AirPlay won't give you the same quality as a hardware connection to a monitor – but since you already have the Macs, it would cost nothing to play with it.
System requirements for Continuity features on Apple devices - Apple Support
https://support.apple.com/guide/mac-help/set-up-your-mac-to-be-an-airplay-receiver-mchleee00ec8/mac
It is no longer possible.
Using iMac as a second screen for Macbook
