Can many buildings be put in a town even if the data is not known?

Hello, I wanted to ask if I can put buildings or houses in a town or city even if the data is not known.
For example, I want to put houses in a town where there are only streets.

If there are buildings on the ground, in reality, you can put them anywhere: inside, outside of towns, villages.

If there are no buildings on the ground, you must not put any buildings into OSM.


thanks, i didn’t know