When you cite a source, you are simply stating that you have used information from that source. You can do this by including the author's name and the year of publication in the text of your work, or by creating a reference list at the end of your work that includes the full details of the source.
When you reference a source, you are providing the full details of the source so that others can find it and verify it. This includes the author's name, the title of the work, the publisher, the date of publication, and the location of the source.
Referencing is important because it allows others to verify the accuracy of your work and to find the original sources of information that you have used. It is also a way of giving credit to the authors of the works that you have used.