In general, you do not do it in Waze. POI data in search comes from other sources like google, foursquare, yelp, etc. (All those options you see at the bottom of the screen when you search for something.)

If it is truly a landmark, it can be added, but almost any business or office, POI, etc., does not fit these guidelines.

These guidelines are also country-specific. If you update your profile with your location info, we can give you better guidance.