"Inuyasha's Daughter" is a fanfiction based on the anime "Inuyasha." The character of Inuyasha's daughter is not true to the anime or the manga, as the character doesn't show up in either.
Inuyash's daughter is a character who was created completely by fans. Her story is retold in fanfictions several times by different fans. There are no official sources that contain information about Inuyasha having a daughter, and the show ends without mention of any children from Inuyasha.
Though there is no indication in the show or the manga that Inuyasha had any children, male or female, as of 2015 many fans continue to write stories in which Inuyasha and the character Kagome have children.