Transformer / How Transformer works

When AC current is supplied to the primary coil, there will be magnetic fields form in the soft iron core.

Since current is alternating, the magnetic fields also alternates

When magnetic field alternates, it will cut the secondary coil, inducing current or emf in the secondary coil

No 

Because, if DC current is supplied to the primary coil, there will be magnetic field forms in the Soft Iron Core, 

But..... this magnetic field will not alternate

so will not cut the secondary coil therefore no induced emf