History is, essentially, the studied of what has happened. Note that this is different from archaeology—which is the study of past events through physical artifacts. History, on the other hand, is predominantly the study of past events through previous writings, events, etc. It has been said that history begins when writing begins. So, when we talk about past events, past people, past documents, philosophies, etc., we are talking about things studied under the umbrella of history. History is a very broad term.

Historiography is the study of historical writing. This is much more specific term, and can include the scrutinization of source usage, writing techniques, and other elements of writing a historically based piece. If you go to college to study history, chances are you will write a historiographical review. That would mean you are looking at a piece of historical writing, such as a peer-reviewed article or a book, and examining the author’s thesis, use of sources, use of background information, argumentation, ease of understanding their writing, and overall writing style to convey their meaning. You would write a review of how well the author wrote their piece, why it’s important, and how it contributes to the historical community. You would also note the author’s strengths and weaknesses, and offer suggestions for better writing.

It’s important to distinguish the two because historiography is a specific sect of historical research. While the study of history in and of itself is very important to uncover new knowledge, the study of historiography allows us to ensure the historical record is being well-written and studied. After all, historical writing influences the way we approach and view history. Without it, the knowledge base becomes much smaller and ideas aren’t spread as well.

Historiography researches and studies how history has been told and/or recorded. Its a narrow, specific term which focuses on a particular subset of the field of history. That subset being studying primary sources and how they survived to this day

History is a much more broad term and encompasses many fields of study, like historiography. In essence its just investigation of the past in all its forms, like archeology, historiography, etc..

A distinction is important because the study of how people record history and how they should be read/interpreted is vital in discerning which information is authethic, exagerated, propaganda, etc..