Blender, being an open-source project, natively supports both the import and export of .GLB and .GLTF files. To export your animation, simply delete all unnecessary lights, cameras, and any other elements in the scene, and export it via File > Export > glTF 2.0 (.glb/.gltf)

The default export format will be .GLB. Leave it as so. Do note that Compression should be left unabled, as compression is not supported in AR.

Make sure all your animation is within the playback range, and hit Export glTF 2.0. You should have a single .GLB file, which will be your final Android product.