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.
Dropbox - Online Sync and File Sharing
Forms On Fire - Forms On Fire provides a complete, customizable mobile forms and workflow system that is reliable and secure, works offline or online.
Google Drive - Access and sync your files anywhere
ProntoForms - ProntoForms is a mobile business solutions application, converting paper forms onto any tablet or mobile device.
Mega - Secure File Storage and collaboration
Safety Culture - SafetyCulture is the operational heartbeat of working teams around the world. Its mobile-first operations platform leverages the power of human observation to identify issues and opportunities for businesses to improve everyday.