You need to gather:

• Blank Scroll
• Rune Writing Kit (Rune Writing Kit Quest)
• Human Bone
• 4,000 gold pieces

Say buy to R'yleth Cth, a mage in Windhowl, and purchase a blank scroll for 653 gold. With the blank scroll, say blank magic scroll, then yes to Araknor, the necromancer in LightHaven.

Kill Araf Kul and/or Roshnak Tul from the Orc camp until you obtain a human bone. Go see Marsac Cred, a wizard in the Mage Tower in Windhowl, with 4,000 gold, the rune writing kit, the blank magic scroll, and the human bone, then say create an enchantment scroll, and yes twice.