It looks like the building was constructed on a concrete slab foundation. The slab is poured in the ground, but not anchored into it. When it's time to move it, you dig under the slab to put in jacks to raise it off of the ground underneath the slab. These jacks also can move it a bit at a time.
For smaller buildings, you might jack it up, and put wheels under it to move it. For smaller buildings on perimeter foundation, you might unbolt it from the foundation to move it, and attach it to a newly poured foundation at the new location.
Repairing a sinking foundation is similar... Dig under, lift up as needed, fill in under the sinking areas, hopefully with something more stable.
Much taller buildings need deeper anchoring. Small buildings on sites with difficult soil conditions need deeper anchoring too.