A family of Microsoft word processing software products for creating web, email, and print documents.
This is now working for me, but took a little bit to find it. I had the same problem. I could see the options for OneDrive, DropBox, etc. But had to dig a little deeper.
In the app (Word, Excel, etc.)
- Press Open
- Press " ... More" in the selection list
- Press "Locations" in the top left of the iCloud Drive header bar
- Press the "More ...." option
- Toggle the Google Drive slider to ON
- Follow the prompts to log into your Google account.
Hope this is helpful.
-Chris