Usually by drawing a closed way around these areas and adding `area=yes`. Do not forget to connect it to the rest of the road network.
**Edit:**
In case it was not clear, as pointed out in comments, `area=yes` is added to any tags, it does not replace any. In your case `highway=service service=driveway area=yes` for the factory and `highway=pedestrian/footway area=yes` for the walkways.