Practically all MPI libraries support Arm64 with the notable exception of Intel MPI.
There is no specific guidance for Arm64 for OpenMPI. It functions on Arm64 exactly as it does on all other architectures. Simply install and use it as you would normally.
There is no specific guidance for Arm64 for MVAPICH2. It functions on Arm64 exactly as it does on all other architectures. Simply install and use it as you would normally.
There is no specific guidance for Arm64 for MPICH. It functions on Arm64 exactly as it does on all other architectures. Simply install and use it as you would normally.