It is the usual high-rate liquid lift method. Each stage adds a small head; hundreds of stages add the head the well needs. Free gas at the intake reduces that head and can lock the pump, so a rotary separator or a shroud is used when the flowing bottomhole pressure is near the bubble point and gas breaks out.
Motor heat and the power cable limit how hot and how deep a well it can serve. Sand wears the stages. The pump adds pressure to the liquid. It does not lighten the column the way gas lift does, and it needs electric power to the wellhead rather than compression.