Can I connect Android to my PI board and manage it like file transfer?
You should explain better … you can us ftp on both easily
Any app or package would do that rather than FTP?
I don’t believe the FTP ,it is not 100% useful ,
As for the transfer app or package , it depends on the size of your files .
You can try it to transfer files to computer and manage them .
See : https://www.tunesbro.com/android-file-transfer-for-pc-and-mac.html
synergy for android allows you to share your keyboard and mouse over to android