Aah ok – that is not a specific font, its part of the system stack GP uses:
-apple-system,system-ui,BlinkMacSystemFont,"Segoe UI",Helvetica,Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol"
So what you see in the editor will be whatever font your system has installed.
If you want the same on the front end then in your Customizer > Typography simply DO NOT select a Font it will default to the system stack.