I will try to explain what I want to do in order to understand if is it possible or there is a smarter way to do it. I daily work with some folders in the Document section of my MacBook, adding/modifying/creating files periodically. Is there a way to link some subfolders of the Document section to the Dropbox folder in such a way when I modify or add some files they automatically (periodically) will be updated in the Dropbox folder and added to the cloud (through the "online only" option)? To better clarify, the main idea is to have a local copy of my files stored in the HDD of my MacBook and an online version of it that upload automatically when I change something inside the local Document section. I hope you can help me, have a great day!
... the main idea is to have a local copy of my files stored in the HDD of my MacBook and an online version of it that upload automatically when I change something inside the local Document section.
Why not just move those folders into the Dropbox folder? That's the point of Dropbox. Move the files and folders you work on regularly into the Dropbox folder, and any changes you make will automatically sync to your account online. Remember, the Dropbox folder is just a regular folder. It's on your local drive.
The other option would be to enable the computer backup feature, which MOVES your Desktop, Documents and Downloads folders into the Dropbox folder so they sync automatically.