How do I open a Microsoft document, excel, or powerpoint file?
Upload or Save the file to your Google Drive
Right click on the file in Google Drive
Hover over “Open With” and select the application needed to open it.
This will allow you to modify the new google document. If you want to convert it back to a Microsoft document, just go to File > Save As > and select the Microsoft product.
By default, Microsoft products opened from your gmail or drive accounts will open in Preview mode.
You'll notice that the formatting may look funny and you are unable to modify the document or spreadsheet in any way.
If you've already opened it in Preview mode, you can easily swap to Edit Mode (a more familiar view with correct formatting),
by clicking on "Open With" and choosing either "Google Docs" for word documents or "Google Sheets" for excel spreadsheets.