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.
Gmail - Gmail is available across all your devices Android, iOS, and desktop devices. Sort, collaborate or call a friend without leaving your inbox.
Dropbox - Online Sync and File Sharing
ProtonMail - Secure email with absolutely no compromises. Get your free encrypted email account today.
Google Drive - Access and sync your files anywhere
Zoho Mail - Zoho Mail is a secure, encrypted, and enterprise-ready email solution, a suite of apps tailor-made for your organization's needs.
Mega - Secure File Storage and collaboration