Define the function using the vararg keyword.

fun printNumbers(vararg numbers: Int) {
    for (number in numbers) {
        println(number)
    }
}

Now you can pass as many parameters (of the correct type) into the function as you want.

printNumbers(0, 1)                // Prints "0" "1"
printNumbers(10, 20, 30, 500)     // Prints "10" "20" "30" "500"

Notes: Vararg parameters must be the last parameter in the parameter list.