export gltf with background image
I have export the GLTF file but on site not showing with light
The environment is not part of the GLTF specification.
It’s up for the renderer to define which environment to show/use. (If you’re hosting the renderer, then you’ll be able to config that).
You could try to add a sphere with the texture and use it as a background… 
I’ve never used this method, so idk if it works.
hdri lighting
we are running this on site from export the gltf
I’m not sure if I’m understanding your problem…
HDRI illumination is done by the renderer and can only be changed when you have access to the API.
The illumination isn’t a part of the GLTF, so there’s nothing you can do in Blender, or in the glb file.
Thanks sir