A: In .NET for .NET6 or later, the built application
entity is implemented in a DLL file.
The EXE file that is output at the same time has
an architecture that loads this DLL file and executes it.
If you specify "Any
CPU" and build an EXE application, the DLL file will be "Any
CPU" managed code, but the EXE file will be native code that can
run on the platform.
Therefore, in a 64-bit OS environment, 64-bit native
code is output for the EXE file. In a 32-bit OS environment, 32-bit native
code is output for the EXE file.
So, an EXE application built in a 64-bit OS environment
can only be executed in a 64-bit OS environment, and cannot be executed
in a 32-bit OS environment.
Please note that it is different from .NET Framework, which can be executed in both 64-bit OS environment and 32-bit OS environment if you specify "Any CPU" and build an EXE application.