A unified theory of the energy and mass flow across the Sun-Heliospheric system requires detailed observations of plasma state and the magnetic field to constrain models of the corona and solar wind. This presentation will briefly summarize the necessary diagnostics to probe the transfer of energy across the corona and inner heliosphere. In particular, highlighting the critical role of PUNCH observations in capturing the extended solar wind evolution to couple with in situ observations of Parker Solar Probe and Solar Orbiter.