Citation generators are simple apps that take bibliographic information and generate citations and references in a desired citation style (such as APA or MLA). However, they are typically "one-off" uses; you may find yourself generating the same citation repeatedly. While there are several citation generators available online, ZoteroBib and NoodleTools Express are both recommended.
Research management software builds a permanent database of references, which can then be used to generate citations and references. Unlike citation generators, research management software will "remember" your library of references, so you don't have to re-find or re-generate the same references over and over. They also come with other useful features for research:
There following software options are recommended to manage your research (in addition to generating citations).
ZoteroBib
NoodleTools
Zotero (full)
Mendeley
EndNote Basic