Depends who owns it / who payed to have it constructed. If the tenets own it and payed to have it constructed, or payed someone who payed someone… Then it’s a condo or a co-op depending on whether you own a unit in the building or own x% of the building which entitles you to a unit.

If another organization, almost always some form of government, payed to have it constructed and owns it then it is public housing.

If it’s anything like cities skylines original, houses just pop up according to demand with seemingly no construction cost calculated, probably because it would add a ton more complexity with mortgages and speculative markets etc. for little gain to players who mostly just want to play with trains and metros.