Why does the file type not change when converting a .PDF to a .PNG?

Question

I was watching a video where the narrator stated that changing a file type from .PDF to .PNG doesn’t change the actual file type of the document. Could anyone explain why ?

In: 2

Answer 1

changing the file extension of a file does not magically convert the contents of said file.

you can convert a pdf to png using software, but simply renaming the file extension will not do that