If the place has a crawlspace, there will be an access someplace, as well as vents. The vents will be on the outside along the bottom, typically below the level of the siding. If there are no vents, then you're built on a slab and there isn't a crawlspace.
Access will either be from a hatch in an exterior wall (which should be obvious, unless a bush grew in front of it) or through a hatch on the floor, most likely in a closet. The hatch may be covered over by stuff.
You can probably see in through the vents- you'll need a light, or have someone shine a light through one vent while you look through an adjacent one. That might be enough to give you a clue about what is happening down there. If there is a side hatch, you might be able to see it. Unlikely you would be able to see a floor hatch.
no subject
Access will either be from a hatch in an exterior wall (which should be obvious, unless a bush grew in front of it) or through a hatch on the floor, most likely in a closet. The hatch may be covered over by stuff.
You can probably see in through the vents- you'll need a light, or have someone shine a light through one vent while you look through an adjacent one. That might be enough to give you a clue about what is happening down there. If there is a side hatch, you might be able to see it. Unlikely you would be able to see a floor hatch.