The gauge singlet right-handed neutrinos are one of the essential fields in neutrino mass models that explain tiny masses of active neutrinos. We consider the effective field theory of the Standard Model extended with these fields under the assumption that neutrinos are Dirac particles. In this framework, we provide a comprehensive study for the phenomenological consequences of various dimension six interactions employing various high and low energy observables such as the proton collisions with one lepton and missing energy or one jet and missing energy, decays of proton, meson, tau and top, as well as the cosmological parameter $N_{\rm eff}$