Your foundation options depend on whether you want the home to be mobile, semi-permanent, or permanent. For mobile use, you should consider mounting the home to a trailer chassis. There are commercially available chassis, from single-axle gooseneck trailers designed for hauling by a pickup truck, to trailers designed to be hauled by over-the-road truck tractors. For semi-permanent use, you can use concrete blocks to support and level the unit, which is the simplest approach. You also can use ISO container leveling legs, and concrete or steel piers with a welded twistloc mount attached, which fits into the corner fittings. For permanent use, you can use concrete or steel piers with a welded twistloc mount, concrete foundation footings along the entire perimeter, or a concrete slab foundation.