RefMe is a free citation management system that helps you organize and store bibliographic data. RefMe works with web browsers and a "WebGrabber" (for Google Chrome) that grabs citation details from websites. RefMe displays formatted citations and in-text citations to be copied & pasted into your word processor. Your RefMe database can be organized into "Projects" and there are robust sharing and social networking capabilities.
RefMe has robust mobile phone and tablet applications available. Check this RefMe Support page (https://refme.zendesk.com/hc/en-gb) for details.
RefMe is a new product, intended to be very simple and user-friendly. To date, there are very few tutorials available -- the current YouTube tutorials demonstrate functions and features that are not very pertinent to the kind of use it is likely that you would make of the database.
There is a link to RefMe Help & Support (https://refme.zendesk.com/hc/en-gb) which can be useful for answering basic questions. I think you will find that you can figure out most of the functionality by experimenting with the database.