EndNote is a tool that facilitates you in making citation references while preparing your research papers, writing theses etc. It also gives you facility to choose any out of many international professionally recognized citation styles like APA etc.
The best feature I would like to share is its ability to handle our bibliographic data. You can download data from many famous and most used online scholarly databases in EndNote based databases. After downloading data you can edit that data according to your needs, you can add pictures and hyperlinks to your bibliographic records.
Optionally you can also enter your bibliographic data in EndNote's database manually no matter it is a citation from a book, newspaper, or a journal EndNote gives you flexibility to do all that with an ease.
There are many more feature out there and waiting you to explore them.