Why did germany and italy become involved in the spanish civil war?

The Spanish Civil War was a major conflict that devastated Spain from July 17, 1936 to April 1, 1939. it began after an attempted coup d'état against the government of the Second Spanish Republic, then under the leadership of president Manuel Azaña, by a group of Spanish Army generals, supported by the conservative Confederación Española de Derechas Autónomas (C.E.D.A), Carlist groups and the fascistic Falange Española de las J.O.N.S. the war ended with the victory of the rebel forces, the overthrow of the Republican government, and the founding of a dictatorship led by General Francisco Franco. in the aftermath of the civil war, all right-wing parties were fused into the state party of the Franco regime.
Republicans were supported by the Soviet Union and Mexico, while the followers of the rebellion, nationalists, received the support of Italy and Germany, as well as neighboring Portugal.
the war increased international tensions in Europe in the lead-up to World War II, and was largely seen as a proxy war between the Communist Soviet Union and the Fascists of Mussolini's Italy and Hitler's Nazi Germany. in particular, new tank warfare tactics and the terror bombing of cities from the air were features of the Spanish war which played a significant part in the later general European war.
the Spanish Civil War received a great deal of attention in the mass media, Ernest Hemingway, Martha Gellhorn, George Orwell and Robert Capa all covered it, and became notable for the passion and political division it inspired, and for atrocities committed on both sides of the conflict. like other civil wars, the Spanish Civil War often pitted family members and trusted neighbours and friends against each other. apart from the combatants, many civilians were killed for their political or religious views by both sides, and after the war ended in 1939, Republicans were at times persecuted by the victorious Nationalists.