Whichever referencing style is used, there is information which needs to be relayed to the reader of your work such as:
who wrote/created it
when was it written/created
what is it
where can it be found
In other words the information required is:
Author
Date of publication
Title of publication
Article or chapter title (depending on the source)
Publisher details
Source location eg URL if relevant
The various referencing styles (APA, MLA, AMA, Chicago. etc.) list the rules on how this information will be presented in your work, both in-text and at the end of your work in a reference list. This includes formatting advice such as capitalization, italicization, and punctuation.