Do fatbike riders lean over like mtb riders?
If so would I be able to ride sitting up if
I changed the handlebars or something else of that nature?

The issue is I have a very bad back.
It's cool when riding sitting up but leaning over is a pain.
I can't say getting a fat bike is a foregone conclusion but
so far you fat bikers have helped a lot.

the physics riding a fatbike are not different from MTB or even motorbikes.
not sure what you mean by sitting, unless you go really off-road you always can sit. Standing si for weight shifting, suspension etc.

I mean sitting upright like on a hybrid bike.
Doesn't the geometry of a fat bike make it harder to ride sitting up?

You should test-ride one, they all will be a bit different.
I sit equally comfortable on my hybrid and fatbike. but with the fatbike I ride shorter distances and constantly pedal (=pushing myself up a bit). Geometry of fat bikes typically goes more in the MTB direction, but not entirely.

you probably can adjust saddle, stem, handlebar etc. to make it more upright. like use a stem that is adjustable and can angle up etc.

Thanks HerrKaleun,you are helping me zero in on what I need to know.
I don't know if I can get a bike shop to let me try one.
The streets get pretty mucky here in the winter.

You got what you paid for.
Quality of the answer depends on the quality of the questions

Sounds like the OP is like myself and does not want to stretch out over an long top tube. I chose a medium frame 18.5" on the Felt DD70 even though I can also ride the large, added a shorter angled up stem and changed to riser bars that were 680mm instead of the 720mm flat bars that came with the bike. Also moved the saddle forward a little in the seat post. I'm happy with the way it feels now.

Well your answer was a good one.
I guess that says it all.

Thanks I had trouble expressing exactly what I meant.
Up to a very short time ago all I knew about bikes was to keep the rubber on the road.
I will see if I can get a test ride and ask them to set it up like yours as much as they can.

B.T.W. nice ride you got there.

There are a few options for raising handle bar height, if that is what you are looking for.
First; is getting handle bars with a high upward sweep, similar to those used on BMX bikes.
2nd is installing a handlebar stem with a angle adjuster. These can swing 60 degrees up or down. They can add about 1-2 inches of height.
3rd is a fork stem extension (also known as a riser). This slides onto the fork stem and adds 2-4 inches to your stem height, thus raising the handle bars.
Hope that is what you are looking for

What do you mean by ”mucky”?
I wouldn’t expect much advantage from a Fat Bike from riding in slush or only an inch or two.
Fat Bike main advantage is when the FB can ride ON snow that’s so deep/dense that regular width tires bog down.
A secondary advantage is when the low pressure and big air chamber can act as suspension for riding over trampled/rutted snow.

Yes you are right mucky isn't quite the right word.
My streets have a lot of dirty salty slush on them.
If I took a test ride the bike's drive train would need
to be rinsed/cleaned and the frame wiped down.
I can understand bike shops wiping down a bike to possibly make a sale but
having to clean the chain,deraileurs and gears is another matter.
Am I wrong about that?

Again, there will be little-to-no benefit from a Fat Bike in slush.
I’d prefer a narrow treaded tire to cut through instead.
As far as the amount of cleaning needed, it’s impossible to say.
Sometimes a shop will have ”demo bikes”. These don’t need to look pristine, as they’re not the ones that get sold. The shop will prepare another bike for the customer to bring home. They only need to be clean enough to look appealing.
Then there is the conditions of the roads at the time of the test ride, length of the ride etc etc.
It’ll take awhile to get the drivetrain thoroughly dirty.
A quick wipe of the chain should be good enough for most purposes.

I know you have to keep repeating how a fat bike's tires won't do what I need them to do.
That is only because I really can't do more than that. It is not just because I am older.
Nine broken bones in my lifetime and several herniated disks don't make for an active off road rider.
It is also because I cannot afford two winter bikes. I have to get groceries and want to travel
around the city by bike. That means my winter bike has to handle pavement a fair amount of the time.
I thought if there were more versatile tires then maybe I could do both pavement and off road.
Black Floyd tires were mentioned and they look pretty versatile. That way I could do off road when able.
The Vee Speedster was mentioned and it was darn close to perfection. Maybe it needs just a tad more tread on the outside.

Yes I know what I need sounds like I need something closer to a mountain bike.
But fat bikes are just so darn pretty.