The People's Commissariats
The Soviet government in Bulgakov's era was called the Совет народных коммисаров [Soviet narodnych kommisarov] or the Council of the People's Commissars, abbreviated as Совнарком [Sovnarkom]. This term was created by Trotsky as an anti-bourgeois name for the bolshevik government. The prime minister was the Председатель Совета народных комиссаров [Predsedatel Sovieta narodnikh komissarov] or the Chairman of the Council of the People's Commissars.
Until 1946, the function of a minister in the government of the Soviet union was executed by a Народный комиссар [Narodny komissar] or People's Commissar, abbreviated to Нарком [Narkom]. A ministry was called a Народный комиссариат [Narodny komissariat] or People's Commissariat, in short Наркомат [narkomat]. All separate Soviet republics, both the autonomous and the federal republics, had a Council of the People's Commissars too.
In 1946, the Sovnarkom was renamed Совет Министров [Soviet Ministrov] or the Council of Ministers, abbreviated to Совмин [Sovmin]. The People's Commissars and the People's Commissariats were renamed to Министер [Minister] and Министерство [Ministerstvo].
Two People's Commissariats played an important role in The Master and Margarita, as well as in Bulgakov's own life. The Народный комиссариат внутренних дел (НКВД) [Narodny komissariat vnutrennikh del] (NKVD) or People's Commissariat for Internal Affairs being in charge of the secret police, and the Народный комиссариат просвещения (Наркомпрос) [Narodny komissariat prosveshcheniya] (Narkompros) or the People's Commissariat for Enlightenment, which, among other things, organized censorship.
The NKVD
In the time that Bulgakov worked on The Master and Margarita, the NKVD was responsible for the secret police, which was called Объединённое государственное политическое управление (ОГПУ) [Obedinyonnoe gosudarstvennoe politicheskoe upravlenie] (OGPU) or Joint State Political Directorate until July, 1934. Then it got renamed into Главное управление государственной безопасности (ГУГБ) [Glavnoe upravlenie gosudarstvennoy bezopasnosti] (GUGP) or Main Directorate for State Security.
You can read more on the NKVD and the GUGB using the link to The Secret Police in the menu on the right
The Narkompros
The Народный комиссариат просвещения (Наркомпрос) [Narodny komissariat prosveshcheniya] (Narkompros) or the People's Commissariat for Enlightenment was the the Soviet administration in charge of national education and other area's related to culture and sciences. This People's Commissariat had innumerable sections which had to keep watch over the political correctness of the various artisctic expressions, and pratctised farreaching censorship.
You can read more on the Narkompros using the link to Censorship in the menu on the right