Hi ​@masa2357, welcome to the Box Community!

At the moment, 'Collections' is only accessible online via web and mobile, and they aren't designed for offline use. Collections offer a great way to organize your content, but they don’t currently support offline access. For more details, feel free to check out our Collections FAQ.

If you’d like to access files offline, we recommend using Box Drive and marking specific folders for offline access. You can find helpful instructions in our Making Content Available Offline guide.

Regarding feature requests, we’d love to hear more about your idea! You can submit it directly on Box Pulse, where our Product Team reviews ideas for future updates. Additionally, feel free to vote on existing features that align with your request.

Thanks again, and don’t hesitate to reach out if you have any other questions or need further assistance!