Probably a given on front as I haven't heard of anything these days that doesn't have wear indicators on the front pads. Only thing I can say on rears is diagram in FSM seems to show pads with wear indicators. Hopefully someone who has changed them can chime in to confirm whether this is true or not.
Usually they are a small metal tab on the disk pad itself. Once pad wears down to a service limit level it starts to rub on the rotor and make a screeching noise.