The Galactic Emperor, also known as the Universal Emperor or Emperor of the Universe, is the absolute ruler and Head of State of the Galactic Empire.
Powers and functions
The Galactic Emperor's power and authority are mainly derived from those of the Supreme Chancellor and the additional rights, responsibilities, and powers bestowed upon that office by the Universal Senate during the Separatist crisis and Clone Wars. It also derives from the Senate itself. The Emperor is the ultimate head of the Imperial Inner Circle, and was, at least nominally or symbolically, advised by the Imperial Senate.
The Emperor is the head of state, the head of government, and the primary commander-in-chief of the Empire, and has absolute authority over the Imperial Military, the bureaucracy, and the entire Empire itself. The Emperor has sole power to appoint, dismiss, approve, and supervise the regional governors. The Emperor organizes and declares the budget, economy, taxes, and trade, ordered the Imperial Senate into session, dismissed it from meeting at will, declared it's agenda, and proposed, rejected, and initiated all Senatorial bills. The Emperor also directs, supervises, and can disband the Courts and has the final say in legal matters. He is immune from any criminal or civil offense. The Emperor can execute, imprison, exile, banish, or confiscate anyone or anything. The Emperor can also issue executive orders, decrees, and proclamations with the legal force of law in the Empire, even more powerful then those issued by the Senate (before 0 BBY). The Emperor supervises, directs, appoints, and dismisses all officials in the government, and creates, disbands, supervises, and directs all governmental administrations, agencies, commissions, and boards.
The issue of Imperial succession is a complicated one. According to law, Palpatine's legal successor is his Sith apprentice and Military Executor, Darth Vader. Vader's successors are supposed to Vader's own apprentices, Galen Marek and Leia Skywalker. And below them, the next man in the succession is Grand Vizier Sate Pestage, then Grand Moff Willhuff Tarkin. However, the Emperor is constantly trying to find ways of living for eternity, to rule forever.