It's often used in English to form nouns that denote:
* The process of writing or recording: For example, biography (writing about a person's life), calligraphy (art of beautiful handwriting), or stenography (writing in shorthand).
* The study or description of something: For instance, geography (study of the Earth's surface), ethnography (study of people and cultures), or cartography (study and practice of making maps).
* The technique or art of creating something: Such as photography (creating images using light), lithography (printing from a flat surface), or radiography (creating images using X-rays).
Therefore, "-graphy" essentially denotes a process, study, or technique related to writing, drawing, or recording something.