Black magic is old science. this is create by Allah to make balance between good and bad. its also create to maintain humanity. black magic used by all religion in whole world with different different name.
In Islam or Muslims its called Evil magic. like Allah Evil (Saitan) is also here. Saitain is created by Allah. and its power called Saitani Shakti or Evil Power or Black magic.
in Islam black magic is used to do two type of work one is good and second is bad. good work like control ghost, know all about specific man or woman, solve people problems etc.
about bad work like kill someone by using black magic, lost his/her business, career, family, money etc.
it will done by good Islamic or Muslim astrologer. they will control jinn power and use his power to do it. if you go to study of Quran then you will able to understand all about it. in the Quran given briefly information about black magic and its relation between Islam.
if you want use black magic on someone then you need to get a good Muslim or Islamic astrologer. without a good Islamic or Muslim astrologer it will given you harmful result or may be it will not work. this will waste your money and time.