Goebbels was the Reich minister of the Reichsministerium für Volksaufklärung und Propaganda, also known as Propagandaministerium. Which translates as the Reich Ministry of Public Enlightenment and Propaganda or Ministry of Propaganda.

The word "propaganda" comes from the term "propagation" which means to spread or promote an idea or belief. Originally the term propaganda did not carry the negative connotations we associate it with today. When Goebbels was made Minister of Propaganda, it simply meant he was in charge of spreading the message of the Nazi party for what he, and his party, considered the good of the German people.

Of course, opponents of the Nazi party, and indeed, those with a relatively ambivalent stance towards the Nazis would not have trusted the manipulated films and newspaper reports which constantly differed from the world they were living in. However, as we have seen in recent years the problem of the term "fake news" being thrown around means people feel obliged to choose a side where their beliefs and trust can lie. In Nazi Germany, there really was only one voice that had total control of what "the truth" could look like.

The horrific acts of public manipulation, what today would be called "fake news" and outright lies orchestrated by Goebbels as Reich Minister of Propaganda is a major factor in why, today, we consider propaganda to have negative connotations.

Words acquire connotations as the years advance. Language is weird like that - and sometimes it can depend on what language. More can always be said on the matter, of course, but you may be interested in just this same question as answered by u/tlumacz.

In addition to being the Minister of Propaganda, Goebbels was also the Gauleiter/Party leader in Berlin. I.e. the leader of the Nazi party in Berlin itself. This was why he was always privy to Hitler's counsels and secrets, and why he had the authority to set up the Volkssturm in th last days of the war.