For hosting common files it's ok. Also it is on Android too do, great to transfer files between your Windows and your phone. But if you want better security you have to subscribe a monthly offer.
Remote Mouse - Turn your smartphone into a wireless touchpad and keyboard now!
Dropbox - Online Sync and File Sharing
KDE Connect - Integrate Android with the KDE Desktop
Google Drive - Access and sync your files anywhere
Monect - Make the best use of sensors on smart device to control PC, simulate steering wheel, game-pad...
Mega - Secure File Storage and collaboration