Feedback mechanisms during the bright phase of active galactic nuclei (AGN) are indicated as the leading processes responsible for the joint evolution of super-massive black holes (SMBH) and galaxies. We investigate the kinematic and physical properties of ionized and atomic interstellar medium gas of well selected AGN-galaxy systems, obtained from UV, optical, near-IR spectroscopic analysis, to unveil the presence of outflows. In particular, we propose and test different selection criteria to isolate sources at z~2 in the predicted feedback phase, starting from multiwavelength information collected in the COSMOS field. As a complementary approach, we also collect a large sample of X-ray selected AGNs at z < 0.8 from the SDSS database to unveil the incidence of outflows and prove the crucial role of X-ray observations for the investigation of the feedback phase. We study in detail the dynamical conditions of the ionized outflows of the high-z samples, for which high spatial resolution data have been obtained. We report the unambiguous presence of fast, massive outflows in 4 obscured QSOs, extending up to 10 kpc in the host galaxy and with profound effects on the host galaxy. We carefully discuss the uncertainties related to the assumption of the plasma conditions in the estimate of the outflows properties and we report, for the first time, the plasma electron density and temperature in a mid-size sample of AGNs. Finally, we combine the ionized/neutral gas kinematic and physical conditions with SMBH accretion and host galaxy properties to infer the general conditions regulating the feedback processes. We also discuss our results in the context of recent observational and theoretical clues.