I think may built-in file viewer/editor na ang mga android/smartphones nowadays. Pero kung wla mn. Try to download and use 3rd party apps i.e. ES File Explorer, File Commander etc. Download mo sa Playstore libre lng.
Nkatry na ako gumawa ng config sa ovpn before. Quite the same lng din ang paggawa gaya ng sa injector at psiphon kasi need ng active ssh acc, remote proxy at payload tsaka need din ng atleast pangtxt or call subscription para gumana.