Sorry that I forgot those details.
My device is an iPad Pro, running iOS 9.3.1. The Adobe Acrobat version is 16.04.05. I just downloaded it from the Apple store yesterday (3/4).
I'm not experiencing any issues, I just would like to know the steps involved in opening a PDF from Google Drive. It doesn't appear that the Google Drive app on my iPad gives me the "open in" options that some other apps do.
Thank you very much, that helped a lot. Are there similar instructions for getting an annotated PDF back into my Google Drive?