Jamieson, Fausset and Brown on Isaiah 45:7

7. form ... create--yatzar, to give "form" to previously existing matter. Bara, to "create" from nothing the chaotic dark material.

light ... darkness--literally (Ge 1:1-3), emblematical also, prosperity to Cyrus, calamity to Babylon and the nations to be vanquished [Grotius] ... Isaiah refers also to the Oriental belief in two coexistent, eternal principles, ever struggling with each other, light or good, and darkness or evil, Oromasden and Ahrimanen. God, here, in opposition, asserts His sovereignty over both [Vitringa].

create evil--not moral evil (Jas 1:13), but in contrast to "peace" in the parallel clause, war, disaster (compare Psa 65:7; Am 3:6).