Why didn't the Fourth Hokage Namikaze Minato seal the Nine-Tails into his own body? Why did he seal it into Naruto's body? Please help me, a prawn

If he sealed the Nine-Tails into his body, the Nine-Tails would die.

When he sealed the Nine-Tails, he deliberately divided the power of the Nine-Tails into Yin and Yang halves. The corpse seal only sealed the Yin side, and the Yang Chakra was sealed in Naruto (Bagua seal). In fact, the other half was sealed. There is a purpose, Jiraiya once said that it was for a jutsu (Chapter 370).

Naruto turned into the Four-Tails because Jiraiya used the key (the key's technique was given to Jiraiya by the fourth generation) to make Naruto's seal twist slightly.

It can be imagined that this technique is very terrifying.

The fourth generation wanted Naruto to learn this technique and inherit his legacy.

"Ninjas exist to protect..."

Due to some problems uploading pictures, I can't upload them here. You can read Chapter 370 online.