php.md

PHP example for SameSite=None; Secure

As of PHP 7.3.0 the setcookie() method supports the SameSite attribute in its options and will accept None as a valid value.

setcookie('same-site-cookie', 'foo', ['samesite' => 'Lax']);
setcookie('cross-site-cookie', 'bar', ['samesite' => 'None', 'secure' => true]);

For earlier versions of PHP, you can also set the header() directly:

header('Set-Cookie: same-site-cookie=foo; SameSite=Lax', false);
header('Set-Cookie: cross-site-cookie=bar; SameSite=None; Secure', false);

For Session Cookie , you can set into session_set_cookie_params method. PHP 7.3.0 introduced new attributes for samesite.

if (PHP_VERSION_ID >= 70300) { 
session_set_cookie_params([
    'lifetime' => $cookie_timeout,
    'path' => '/',
    'domain' => $cookie_domain,
    'secure' => $session_secure,
    'httponly' => $cookie_httponly,
    'samesite' => 'Lax'
]);
} else { 
session_set_cookie_params(
    $cookie_timeout,
    '/; samesite=Lax',
    $cookie_domain,
    $session_secure,
    $cookie_httponly
);
}