Is there any possible way to create html annotation in gltf using three.js
Yes, using CSS2DRenderer could do the trick here. There is also an official example that demonstrates the basic usage:
This blog post is good, too: https://manu.ninja/webgl-three-js-annotations
Is it possible to create THREE.SphereBufferGeometry as a child of my mesh or material. as child to the nearest THREE.Object3d. and some one could you explain how to show in using THREE.Raycaster , when click the child which popup the html div.