What happens to the magnetic flux when it passes through a ferromagnetic substance?

Ferromagnetic materials are made up of small domains which itself is like small magnets

As soon as these ferromagnetic materials are placed in external magnetic field the domains aligns itself in the direction of external field and hence the net magnetic field inside the domains will increase.

This way we can say that net magnetic flux when entered inside the ferromagnetic material it will increased due to increase in the net magnetic field.