Best design pattern to handle iOS Application State/Data

I am starting a new project (learning purposes) and I am trying to figure out what is the best software design pattern to use in the following scenario.

I have several data that need to be downloaded from multiple webservices and store somewhere in my app, to display it later. However each piece of data (e.g. list of teachers, students) will only be used in one or more specific view controllers (e.g. teachersViewController and studentsViewController).

I read that the Singleton pattern or use the AppDelegate to store a variable (an object like ApplicationData) is a bad practise, even more in this example which I want to restrict the data access.

So, which design pattern should I choose? I have read something about dependency injection, but I don't have any clue about it or if it even helps me in this question. If it helps, some examples with explanation would be nice.