“The Bloomberg Terminal is a proprietary database that allows the user to perform analysis and obtain real time and historical pricing on a range of securities from stocks, to bonds, exchange rates and collaterialized mortgage obligations (CMO's)” (description courtesy of New York Institute of Technology Library)
It has to be used while on Campus. There is no off-campus access now (During the COVID pandemic, they temporarily allowed off-campus use). You might run into academic download limits if you are trying to pull a lot of data. See Columbia University Libraries guide for more information about the data download limit and basic Bloomberg information: https://guides.library.columbia.edu/bloomberg/downloadlimit