“Move” Vs “Copy” Folder To iCloud Drive?

I know there are already lots of Q and A about icloud drive. Here’s another: I’m running El Capitan on my imac. I have a Documents folder in my home folder. Is there a difference if I “move” or “copy” that Documents folder to icloud drive? I want to keep a copy locally on my imac (and available offline), but also have it available to access from my ipad. I understand your explanation about the “optimize mac storage” button, but since I’m running El Capitan, I don’t have that when I look at icloud drive options. So, given my OS, what’s the best way to deal with my documents folder and accomplish what i’d like?
thanks very much!
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bob