Ancient history

How does Naruto feels when he becomes the 6 Hokage and Kakashi tells him that fourth is his father?

In the Naruto series, Kakashi never reveals to Naruto that his father is the Fourth Hokage. It is not until much later in the series that Naruto learns this truth from other sources. Therefore, Naruto does not experience any particular feelings associated with learning this information while becoming the Sixth Hokage.