Help with script

Godot Version

4.2

Question

why my script is not working:

extends Node3D

func _input(event):
	if event.is_action("npc"):
		var enemy_scene = load("res://enemy.tscn")
		var enemy_instance = enemy_scene.instantiate()
		add_child(enemy_instance)
		enemy_instance.position3D = $Player_character.position3D

If position3D does not specialize in your code you should use position instead

extends Node3D

func _input(event):
	if event.is_action("npc"):
		var enemy_scene = load("res://enemy.tscn")
		var enemy_instance = enemy_scene.instantiate()
		add_child(enemy_instance)
		enemy_instance.position = $Player_character.position