I am not able to copy my pdf files to my device. It always shows an error occurred. When I open the file on device it can not be opened because the file format is not supported
It seems like a file-specific issue, the file is not downloaded on your system. Here I would like to know few details for a better understanding.
Please try to save your file in Adobe Document Cloud, and then try to open it via the application. You can sync your files to Adobe Document Cloud and get instant access across desktop, mobile, and web.
For your reference: https://helpx.adobe.com/in/mobile-apps/help/adobe-scan-faq.html
Hope this helps. Please let me know if this works.