Answer:
There are certain functions which every government has to perform, no matter what ideology or political system is in use. Every government must be able to repel an invasion by a foreign power. It must enforce some reasonable set of laws so that private citizens do not murder, rob, or rape each other at will. It must have some system of currency. It will have regulations concerning immigration, exports and imports, and other matters of national concern. It will have ambassadors that are sent to other countries to conduct diplomacy.
In a liberal democracy, the concept of human rights becomes important and the government takes some care to protect the rights of individuals. In both fascist and socialist societies, the emphasis is more on the rights of society than on the rights of individuals. People are often arrested and may be tortured or executed by dictatorial governments without any due process of law. People are arrested for having political opinions that the government wishes to suppress, rather than because they committed any actual crime. In some cases, minority groups are severely persecuted, even to the point of mass murder. Fascism can also be considered a form of socialism, and let us remember that the actual name of what we now usually call the Nazi party was the National Socialist party. Nonetheless, it is still possible to distinguish between socialism and fascism. Fascism typically is very militaristic, and may involve grand schemes of world conquest, but it also believes in the free market and allows private businesses to function freely. Socialism prefers the command economy in which the government owns everything, employs everybody, and makes all economic decisions.