<?php
$array1 = [
"color" => "green"
];
$array2 = [
"color" => "red",
"color" => "blue"
];
$result = array_merge($array1, $array2);
?>
// $result
[
"color" => "green"
"color" => "red",
"color" => "blue"
]
$output = array_merge($array1, $array2);
$all_arrays = array_merge($array1, $array2, $array3, ...);
$a1=array("red","green");
$a2=array("blue","green","yellow");
print_r(array_merge($a1,$a2));