Are asset bundles platform specific?

I am relatively new to unity and am trying to use asset bundles for the first time. This is a project which needs to be integrated in many different platforms: android, ios and web. The project is working for right now, but I need to add more asset to it at runtime, so I decided to add new assets as asset bundles in project.

But from the documentation I got to know that they are most probably platform dependent. Can anyone explain me that how can I make and use asset bundles for multi platform games? And also guide me how to store these assets in these platforms so that user don’t need to download it every time they use it. Thanks.

The Asset bundles cache can be used to avoid downloading the same bundles each time:

AFAIK they are platform dependent. In order to let players download them form different platforms, you need to build them for each platform and let the player download the correct one.

About storing, I am not sure, but I’d say it’s just files you download and store somewhere on disk, it’s up to you to do it. But there might be some built-in solution.