You just add more plumbing risers and put point of use water heaters in the units. You might need to upgrade the building water service to accommodate higher water usage, but it’s literally just adding pipes and pumps in an existing mechanical chase or core drilling thru each floor to add plumbing risers. Some really tall buildings have tanks on top of the building to provide water pressure at the top via gravity.

You can add drainage the same way, you just don’t need pumps for the drain stacks.