In PHP, you can store elements in a multidimensional array by assigning values to the array using an index or key. A multidimensional array is an array that contains other arrays as its elements, and each of these nested arrays can contain its own elements, and so on.

To create a multidimensional array in PHP, you can use the array() function or use the square bracket notation []. Here is an example of how to create a multidimensional array in PHP using the array() function:

$array = array(
array(1, 2, 3),
array(4, 5, 6),
array(7, 8, 9)
);

Here is an example of how to create the same array using the square bracket notation:

$array = [
[1, 2, 3],
[4, 5, 6],
[7, 8, 9]
];

To access and modify the elements of a multidimensional array, you can use multiple sets of square brackets to specify the indices or keys of the elements at each level of the array. For example, to access the element 5 in the above array, you

could use the following code:

echo $array[1][1]; // Outputs 5

To modify an element in the array, you can assign a new value to it using the assignment operator =. For example, to set the element 5 to the value 10, you could use the following code:

$array[1][1] = 10;

You can also use loops and other array functions to iterate over and modify the elements of a multidimensional array. For example, you can use a nested loop structure to iterate over the elements of the array and perform some operation on each element.

Here is an example of how to use a loop to iterate over the elements of a multidimensional array and multiply each element by 2:

for ($i = 0; $i < count($array); $i++) {
for ($j = 0; $j < count($array[$i]); $j++) {
$array[$i][$j] *= 2;
}
}

This code will multiply each element in the array by 2.

You can also use the array_map() function to apply a callback function to each element of the array. For example, you could use the following code to square each element of the array:

There are many other ways to store and manipulate elements in a multidimensional array in PHP, and the best approach will depend on your specific needs and requirements.