We report on a detailed study of the dynamics of charged and neutral excitons in modulation p-doped CdTe/CdMgZnTe quantum wells by degenerated four-wave mixing and time-resolved photoluminescence experiments under resonant excitation. The study of the charged and neutral exciton homogeneous linewidth as a function of the temperature and of the quasiparticle densities shows that the charged excitons are localized in the fluctuations of the electrostatic potential induced by the remote dopants. The time-resolved photoluminescence experiments allow us to extract the formation time of the charged exciton (65 ps) and experiments performed in a transverse magnetic field show that neither the spill orientation nor the spin coherence of electrons is destroyed by the formation process of charged excitons via exciton states.