How can I stop animals from going under my mobile home?

Lattice is fairly inexpensive skirting.

There are lots of sites which can offer you detailed DIY information. Google “installing skirting on mobile home”. Folks have great ideas and shortcuts.

I would still block it off but put a vent in so it can air out.

Oh, yes, the armadillos are there, and maybe the possums, too. But they are looking for food. One thing you could do is put down Sevin dust all under your home, followed by a thick layer of plastic, and a thick layer of big rocks. A better option would be to pour a thick layer of cement, leaving access to water and gas lines. Then underpin again with blocks set into the ground two deep, then up to the mobile home bottom. But leave a gate or removable panel for repairs. Paint the blocks to match your home, or another color you like. If you have to pay someone for some of this, see what you can pay for with a chicken dinner. Those critters can sound like a feral hog and actually shake your home. If you can’t get rid of them, wear earplugs! Best wishes ☺️

Put down moth balls

go to lowes or home depot and get one of their deer away (animal)away smells for a min when sprayed,but goes away seems to work

Moth balls in my car trunk keep mice out!