Using Google Drive, open the document.
Tap the More Options or Caterpiller button (three vertical dots in the upper-right corner) and select Share & Export.
Choose Send a copy
Choose Format PDF
Select Import with Notabilty.
After Notability opens, choose Create a New Note then tap the Import option in the top-right corner.
If you are doing this to work around a problem with printing a Google Doc, print the Notability note you just created.
You can access print in Notability via the share icon: