Spam Quarantine, Spam Folder, and Mark As Spam

Spam Quarantine, Spam Folder, and Mark As Spam

In my Zoho Mail account, what is the difference between the Quarantine (in Control Panel > 
Mail Administration > Spam Control), and the Spam Folder in my Email Account? My Quarantine is empty, but my Spam Folder has 148 messages. 

I just found that a few legit messages were marked as spam, and moved to my Spam Folder, so I had missed them. Yet, my Spam Control settings are all set to "Allow Email". 

Is it possible to send ALL message to my Inbox, but mark/tag the likely spam messages with "[SPAM]" in the Subject line?

If not, how can I make the spam filter less aggressive?

Thanks.