So, Vatican City is a very small country that is actually located inside the bigger country of Italy. Even though Vatican City is very small, it still needs to have people who make important decisions, like how the country should be run.
To do this, they have something called electoral districts. Think of them like different neighborhoods within Vatican City. Each neighborhood has a certain number of people who live there, and those people get to vote on who they want to represent them in the government.
But because Vatican City is so small, there are only two electoral districts. One is called the Apostolic Palace District, and the other is called the St. Peter's Basilica District. These districts were created to make sure that everyone who lives in Vatican City has a voice in how the country is run, even though it's very small.
So basically, electoral districts in Vatican City are just different neighborhoods within a very small country, where people get to vote for who they want to represent them in the government.