Google Drive at its core is really just a cloud storage space. With Google Drive we have a lot of storage, probably more than you'll need for just documents and spreadsheets alone. You can also upload a variety of other file types such as movies and pictures.
To upload a file first open Google Drive. Click new then File upload. Browse through your system to find the file that you want to upload and click Open. You can upload more than one file at a time or you can upload an entire folder at once, by selecting Folder upload instead of File upload.
By default Drive will open PowerPoint files in Slides, Word files in Docs, and Excel Files in Sheets. If you download this extension you will be able to edit the files in their native format. Otherwise, Drive will make a copy in the corresponding Google App's native format.