What is meaning of _ in Swift func ?

Ans : 

The _ is used to define that the parameter is not named

If you have multiple _ it states that you do not need to name the parameters in your function call

func myFunc(name:String, _ age:String){       }

myFunc(“Milo", "I'm a really old wizard")

If you do not use the underscore you would use 

myFunc(“Milo”, age: "I'm a really old wizard")

The _ is not necessary in function calls. It is just used to indicate that something does not to have a name.