You can synchronize your Mendeley collection across computers, devices, and the cloud-based back up.
When you are in Mendeley Reference Manager', click on the 'sync' icon in the top right corner.
Citations can be stored in more than one folder.
To copy a citation into another folder, locate the citation and click and drag it into the destination folder.
To create a folder in your Mendeley Reference Manager:
On the left side of your screen, click on 'New collection'