I have a question regarding this code:

struct Player {
    let name: String
    let number: Int

    init(name: String) {
        self.name = name
        number = Int.random(in: 1...99)
    }
}

let player = Player(name: "Megan R")
print(player.number)

Why cannot we just do following:

struct Player {
    let name: String
    let number = Int.random(in: 1...99)

}

let player = Player(name: "Megan R")
print(player.number)

Welcome to Hacking with SwiftUI!

You're asking a question from Day 10 from a lesson titled How to Create Custom Initializers

See -> Day 10 Lesson

struct Player {
    let name:   String
    let number: Int // 👈🏼 This is a place holder. It must be initialised somewhere.

    //   👇🏼 This is a custom initializer. It's the focus of the lesson.
    init(name: String) {
        self.name = name
        number = Int.random(in: 1...99) // 👈🏼 Here! Initialise it in a custom initialiser.
    }
}

let player = Player(name: "Megan R")
print(player.number)  // prints "42" (probably)

There are a few ways to initialise a struct's variables and you offered an example in your question above. That's a fine way to initialize a variable, but it doesn't illustrate the process of using a Custom Initializer.

Keep Coding!