How do YOU organize documents on your Android

On FB I asked

"DEAR HIVEMIND: How do YOU organize documents on your Android device? I have about 4 categories of documents I need to review on the bus; each category would get its own folder but I don't see how to do that on my fancy new Android tablet. Do I have to download an app - this isn't native? And what app do you prefer?"

Answers

• I'm no help at all. I only stream on my Android. 
• I use Google Drive, which is where I store everything anyway. That way I don’t have to reorganize everything, just access the cloud. 
• Another option is Evernote (https://www.evernote.com) which keeps track of all kinds of information if you want it to. Adding documents in folders (notebooks) is simple and straightforward.