If you are unable to edit Microsoft word doc files saved in your Google Drive in your Android phone or tablet, you may have to go through some extra steps to get working.  Usually, when you tap a doc file in Google drive, it opens the file in google docs and as you scroll down an edit icon (pencil symbol) should appear somewhere at the bottom right half of your doc file. To start editing or making any changes to this file, you simply select this icon. However. If you do not see this edit icon on your Google doc file, please follow these steps:

1. Open Google Drive on your Android device
2. Now tap or select the three dotted icon next to the doc file you want to edit
3. Select “open with” >> Google docs
4. Now the file will open in Google doc 
5. Tap the edit icon to start editing and hit the save icon once you’re done marking changes.
6. On Android phone, scroll up and tap the tick mark on the top left to save changes. On PC, the changes will be saved in real-time