Apartment Complexes

I’m not sure how apartment complexes can be tagged in OSM. Completely new, just joined a few days ago.
At least in my area and the surrounding cities, apartments will consist of several buildings located at a single street address. Each building has a building numbers and numbered apartments.
As a delivery driver, these can be very confusing and frustrating especially when the customer doesn’t even know how the numbering works for their complex.

This is typically in the format of:
Building 1 Floor 1: Apt.101, 102, 103
Building 1 Floor 2: Apt.121, 122, 123
Building 2 Floor 1: Apt.201, 202, 203, etc…

But sometimes there are:
Building 1: Apt.1, 2, 3, 4,
Building 2: Apt.5, 6, 7, 8, etc…

And also:
Building 1 Floor 1: 101, 104, 107
Building 1 Floor 2: 102, 105, 108
Building 1 Floor 3: 103, 106, 109, etc… ← This is the worst one because nobody figures it out the first time they visit.

But basically, apartment number assignment is arbitrary and chaotic.
The written address never includes building numbers, although they are always marked on site. Sometimes they are not easily visible though due to foliage or being unlit at night. Apartment addresses on all of our store’s documentation have this format:
2400 Open Street, Apt 1204

I’d really like to make OSM usable for finding apartment locations at least to the location of the building. The largest complex we deliver to has 24 buildings, in a weird layout that buildings 21-22 are next to 12 and 15. There are also some newly built complexes that look like all the buildings have 8 or 10 floors with a parking garage on the ground level.
So far, I’ve been using StreetComplete to fill out road information in my area but I want to start drawing houses as most of the neighborhoods here are just roads. Making it a replacement for Google Maps is my goal since OSM can hold more useful data such as having marked the private gates, which makes navigation *much *better. Google will always try to drive me through the gate of a high-security commercial complex or gated community’s strictly residents-only entrances.

It is possible to add each address separatedly. I would suggest to place them near the entrance where you can enter/access the building.

Would I add that as a point with address tags on it?
Like this?: addr:unit 101,102,103

You want [pre]addr:flats=[/pre] for this.

Yes, that would be a point.

Hi Have a look here, https://www.openstreetmap.org/#map=19/52.34098/6.67715 or this one https://www.openstreetmap.org/#map=19/52.34226/6.67967, 7 (apartments) & 4 floors / levels. All the numbers are for a house or just a room to rent with a service contract for a close guidance and service (known as a service flat / condo).