What is an authoritarian form of government? The very fundament of the system is a strong centralized power. It tries to restrict the public from participating in politics. So, it ties down political pluralism. That is the idea that a free society can only remain free if people engage in politics. Thus, more opinions can emerge, and people have a say in things. Yet, that does not occur here.
This kind of state tends to limit elections. They cannot be free due to limited pluralism. And, you cannot vote out the leader or group of leaders. Besides, independent organizations cannot criticize the state. The free press is also confined. Hence, it is in contrast to democracy.
Besides, there is no clear ideology behind such a government. All authority concentrates in the hands of one leader or a small group. In addition, their behavior and powers often shift. Emotions are their most influential tool. Emotions are vague, formable, and they change in time. Further, they tend to have a strong military.
But, an authoritarian government is different from a totalitarian. It is namely the lack of ideology that makes it different. In addition, a totalitarian regime is much more strict. Yet, both suppress the citizens. They like to control the people.
In practice
The rise of authoritarianism was in the 20th century. In the 1920 and 1930s, vigorous authoritarian states arose. Among these were Portugal, Spain, Poland, Tukey, or Argentina. Besides, totalitarian regimes took over Italy, Japan (fascism) Germany (nazism), and the Soviet Union (communism).
After World War II. ended, fascism and nazism fell. On the other hand, communism spread over Eastern Europe. These were usually totalitarian. Yet, a case of an authoritarian state was Yugoslavia.
Besides Russia, Turkey, or China, many such states are in Near East and South Asia. For instance, Saudi Arabia, United Arab Emirates, or Vietnam. Other such states lay in Latin America, e.g. Venezuela.