How does Google Scholar generate the citation information of articles? (in different styles like MLS,APA,etc). Do authors have to enter it themselves? Asking because I want to know how authentic this is and whether I can directly copy the citation as it is. without reading any style guide myself.
Google Scholar gets the information (title, authors, journal name, date,...) directly from google scholar indexed journals. It produces the different styles from that information. Usually this works quite well, however, sometimes things go wrong so it's always good to check if everything is correct.
I also recommend using a citation manager like endnote or mendeley, that way you can download citation styles directly from the source/journals, manipulate them, easily change styles and correct errors.