Before the update 1.16.0, you could download addons on mobile and play them. When downloaded, they would go to the resources and behavior packs. When they are downloaded, then you can activate them and then they are in that world of Minecraft ready to play. That's what's supposed to happen. And it did in the past version. But now in the new version 1.16.0, you can activate them to your world, but they are not there in that world. So when the resource or behavior pack is activated in that world, you still can't see it or use it in that world once in it.