If the array is NSArray you can use the adding
function to add any object at the end of the array, like this:
Swift 4.2
var myArray: NSArray = []
let firstElement: String = "First element"
let secondElement: String = "Second element"
// Process to add the elements to the array
myArray.adding(firstElement)
myArray.adding(secondElement)
Result:
print(myArray)
// ["First element", "Second element"]
That is a very simple way, regards!