Unitary government – It has one type of government. Power is not divided.Federal government – It has two or more type of government. Power is divided between different levels of government.
Unitary : only 1 govtFederal : more than 1 level of govt

Federalism is a government in which powers of the government are divided between the central government and the governments of the constituent units of the country.Unitary form of government is a government in which all the powers of government are concentrated into the hands of one central government and all the units are subordinate and under the central government.

Unitary is state government whereas federal is union government.
Federal and union are same