I am assuming we’re talking about able-bodied and mental well people - the disabled are a different issue I’ll address in a bit.
I agree with iiandyiiii about some of his minimums so I borrowed freely, but here’s my list for able bodied mentally healthy people as a rock-bottm:
200 square feet per person living space total. (As a comparison - my very first studio apartment was about that including closet and bath so I have some experience with this). For a single person that would probably be a studio apartment. For a two adult family with four kids that’s around 1200 square feet (because there’s six people). I don’t care if that’s government sponsored, or if you give the folks a voucher to rent from a private landlord (remember - we’re talking about able-bodied mentally well people, which to my mind excludes alcoholics, drug addicts, non-functional mentally ill, etc.) Studio apartments would have at least a toilet, sink, and small shower. Family units should have a little bit larger sanitary facilities, in other words, if you have a family group I would rule out a bath tub.
Medically necessary health care.
A safe and temperature-controlled (>60 F in winter, <80 F in summer) place to sleep. Depending on climate that would require heating or cooling, and certainly a lock on the door.
Access to nutritious food and a means to cook it. I’m OK with the current SNAP program in the US, although there could be some tweaks. I like it a lot better than handing out food to the poor. There should be a kitchenette of some sort - sink, stove, fridge, small pantry/storage - but it doesn’t have to be lavish.
Access to personal toiletries/cleaning products/etc. Can’t use food stamps for toilet paper although if you eat you will at some point need toilet paper. I’m totally OK with a monthly stipend for this sort of thing, on par with what’s done for food.
Adequate clothing for the climate and work they do, plus at least one casual and one more dressed up outfit. So in northern areas that would mean winter coat/gloves/hat as well as regular clothing. Two pairs of shoes, or a pair of shoes and a pair of boots per year. Also adequate bed linens, towels, etc.
Access to laundry facilities
Basic phone and internet access. Because good luck applying for a job these days without one. Also, useful for contacting social service agencies, keeping in touch with family and friends, entertainment, etc.
Those are minimums. If a particular individual acquires a TV (donation, saves their pennies, gift from someone, doesn’t matter) I don’t care. If they can save up and by themselves another pair of shoes, or convince an apartment building manager to let them garden out back that’s fine. I don’t care if they have a book case or a few personal possessions. They’re poor, not prisoners. If they work odd jobs or a few hours a week so they can get themselves the occasional goody I’m fine with that.
Now, for the disabled/frail elderly they might need consolidated housing - they’d have a studio apartment, but access to, say, laundry or cleaning services or food services (like meals on wheels) that would probably have to be at least somewhat subsidized but in that case it would be people who qualify for those services.
For the mentally ill/chemically dependent/intellectually impaired other types of housing might be more appropriate. There are mentally ill people who really would be better off in long-term inpatient housing. We might not want drug addicts cooking, so more of a controlled living situation with a cafeteria type food service. I’d have to think a bit more about those situations.