Can’t attach documents

I have always used the mail app from apple with my ipad pro and iphone. I thought I would give the gmail app a try. Sometimes the mail app is slow. Initially the gmail app was great. Faster than the mail app. A different format, but good. But, when I tried to attach a document from someplace other than google, then it was a problem. You can not attach anything from Dropbox or icloud. Not good for me. Keep trying google.

AoGI ambassador about Gmail - Email by Google, v5.0.171217