Micro inverters provide one small inverter per panel up on the roof. These are easier for engineering, multiple system expansions and for shaded roofs
String inverters or central inverters will have one large inverter for the entire system located on the side of the house. Modern string inverters will have MPPTS or Optimizers eliminating the problem of one panel failure resulting in the loss of the entire system or array
Either way…your solar energy gets inverted! (from DC to AC power)