Collision of 2 objects, which one should be is-Kinematic

I am confuse, as to which out of the two objects e.g a 2 sphere balls on a cubic box colliding with each other, should be is Kinematic.
Who should have rigid body component and why the other should not have?
Where I should tick mark “Generate colliders”–> cubic box, 2 sphere balls? where?

I got so so confused that I even want to know that is Static Collder the same which we get through “Generate Colliders”

Any expert around here please help and guide. I would be truly grateful to you.

regards,
Ent

Your question is not very clear.

If you just want two balls to interact, then make both of them rigid bodies and give both Sphere Colliders. Neither should be marked as kinematic.

“Static Collider” is a name for an object without a rigid body, but with a collider attached.
I assume that the box you mentioned is an unmovable object. If so, then it should be a “Static Collider”. So do not attach a rigid body to it (neither dynamic, nor kinematic), but do attach a Box Collider to it.

The “Generate Colliders” option is for generating Mesh Colliders for imported meshes. Do not use it for boxes and spheres, since it’s a waste of resources. Use it only for objects that can not be approximated with boxes, spheres or capsules.

In other words:

Sphere1: Rigid Body (Not Kinematic) + Sphere Collider

Sphere2: Rigid Body (Not Kinematic) + Sphere Collider

Box: No Rigid Body + BoxCollider

…and do not use “Generate Colliders”