By 1941 most of Europe was controlled by Nazi Germany, only five nations were neutral, Ireland [Eire] Portugal, Spain [ though some volunteers fought for Germany] Sweden, and Switzerland.
Visible signs of Nazi occupation were the presence of German troops, curfews, rationing, and large doses of Nazi propaganda. The structure of government for the occupied territories varied, in some countries the Germans retained existing governments, though under strict supervision. In Poland, the Baltic states, and the occupied areas of USSR, nation states were abolished, and total Nazi rule established. For Belgium and Northern France [ southern part under Vichy control] there was a military government, with less SS and Gestapo involvement, but in Holland there was a civilian occupation regime [The Reichskommissariet Niederlande] brutal at times, with SS participation.
Hitler considered Denmark as an “Aryan country”, and its elected government was allowed to continue with light German supervision, Hitler had hoped that Denmark would support him in his fight against Communism, but the nation, including the Royal family were not very cooperative, and in 1943 the Nazi's took full control. The impact on civilian life in occupied Western Europe varied, and initially was rather benign, Hitler viewed the Western Europeans mainly as similar to the Germans, and treated them in a more reasonable manner, however resistance was met with severe punishment.
Curfews and censorship were widely imposed, and movement was restricted, citizens were regularly stopped and searched, food, clothing, and petrol rationing was introduced, and the occupied countries were stripped of resources, to meet the needs of the occupiers, and to assist the German war effort. To make up for the shortage of food, citizens had to make do with rather distasteful alternatives, such as Ersatz coffee made from acorns, wooden shoes instead of leather ones, and a greater use of bicycles replacing cars. Coal and firewood disappeared, as did soap, a black market thrived. Shortages were worst in cities, and as the war continued so hardships intensified.
Thousands starved in Greece during 1941-42, and in Holland during the winter of 1944-45 an estimated 6,000 people died of starvation. The impact of Nazi occupation was at its very worst in Eastern Europe, Hitler considered Slavic peoples, Poles, Russians, some nations within the Baltic states, and above all the Jews to be subhuman.
The Nazi attitude towards occupied Eastern Europe was completely different, the administration of this area was was deliberately cruel and murderous, this was the area designated for German Aryan settlement [Lebensraum], the native population, such as Communists,Jews, Poles and Russians were rounded up, Jews in particular were victims of mass shootings.
For Adolf Hitler and the Nazis, this was in the main a racial war, with the Jews their prime enemy. they were persecuted throughout Nazi-occupied Europe, very soon after German forces occupied a country, local officials were ordered to provide lists of all Jews, who were then stripped of all rights, banned from schools, restaurants, and public places, they were removed from public office, and the professions, their businesses shut down.
From 1942 onwards the persecution of the Jews escalated, Eastern European Jews were removed from Ghettos to death camps, and mass deportations from Western Europe commenced , this included German Jews, most were to be murdered in death camps such as Auschwitz, in total around six million Jews were exterminated, it is estimated that in addition five million non-Jews were murdered, in and outside the camps.