Google Drive is basically your hard drive on the Internet or to be fancier, 'in the cloud', so that you can access your data anywhere in the world as long as you have Internet connection.
Google does the maintenance and dirty work of backing up your data so that you will NEVER lose your data. In fact the chance of you losing your data is even lower than the chance of losing your data stored on a physical hard drive!
I use Google Drive to store many documents including photos, work documents, powerpoint presentations, spread sheets, everything.
Google Drive is easy to use. Simply drag your files on a Windows explorer to your Google Drive program or online account and Google Drive will upload them for you!