If you see “(32-bit)” and you are running Firefox 56.0 or older, updating to the latest Firefox version should automatically upgrade you to 64-bit.
Ma twalaḍ "(32-bit)" ticki tesselkameḍ Firefox 56.0 neɣ aqbur, asader n lqem aneggaru n Firefox ad k-yessali s wudem awurman ɣer 64-ibiten.