Google drive app if you just want to manage your data in the drive you have. Google docs if you wish to edit the file. Also google docs if you just want to work with doc files as google docs will list all previously edited files in the app.
Will we ask the question do I need Word if I have a file explorer?
When I have a .docx file on Google Drive - will I need the Google Drive App , the Google Docs app or should I just get the Microsoft Word mobile app?