Most likely, you don't need either of them. Especially if you don't know what they do. Check out Scid and Lucas Chess. 100% free and great software that will fulfill pretty much all of your needs.
To answer your question, Fritz is much more about using the fritz engine for training and analysis while ChessBase is much more focused on storing, searching, filtering, and data-mining large collections of chess games. The interface is very similar between the two products and they share many features.
Id like buy one chess sofeware,but dont have any idear , Is any suggestion?