Google Drive is Google's version of the 'cloud'. You can access, save & edit your files online at http://drive.google.com. You can also create a synced copy of your files on your computer, so you can access & edit them even when you do not have access to the internet. Google's strength is in collaboration - sharing documents and folders with others so several people can view or edit them at the same time.
Google Docs (like MS Word)
Google Drawings (like Paint)
Google Forms (surveys, quizzes, etc.)
Google Sheets (like MS Excel)
Google Slides (like MS PowerPoint