A pivot point is the reference point around which a rotation or scaling operation takes place.
A door makes the difference easy to see
Rotate a door around its centre and it spins like a sign. Rotate it around the hinge and it opens. The geometry can be identical in both cases; the pivot changes the motion. Scaling also depends on the pivot: enlarging an object around its base can keep its feet planted, while enlarging it around its centre can move the base downward.
Pivot and origin can coincide, but need not
Many tools use the object origin as the default pivot. Others allow a temporary pivot at the selection centre, a cursor or another point. That temporary editing choice does not necessarily alter the exported asset. A parent object can also provide an offset rotation centre when a file format does not store a separate pivot property.
For an animated artwork
A butterfly wing, a book cover or a hinged frame needs a sensible rotation centre to feel believable. When preparing such a model for Painta, verify the motion in the exported GLB as well as the authoring scene. The animated comparison shows the same panel turning around two different points; it helps diagnose an orbiting part without changing its shape.