In free-space communication, partially coherent fields are more resistant to atmospheric turbulence, resulting in reduced beam loss and less scintillation at the detector. In this article, we used the Glauber-Sudarshan P function analogy to study the nonclassical properties of the m-photon-subtracted (or added) squeezed vacuum state generated from a partially coherent Gaussian Schell model pump. Utilizing a novel formulation, we examine the Wigner distribution function and decoherence of the Wigner distribution function of these partially coherent multi-photon-subtracted (or added) states in the amplitude decay model. Further, the nonclassicality and non-Gaussianity of these states, along with the purity of the photon-added two-mode squeezed vacuum state, is analyzed. Our findings show that by optimizing the squeezing parameter and pump parameters, the partially coherent pump can produce multi-photon-subtracted (or added) squeezed vacuum states with partially coherent properties while preserving the nonclassicality and non-Gaussianity in these states. We expect these results to be useful for long-distance quantum communication, quantum metrology and quantum sensing.