report.php

<?php
$ch = curl_init();

$data = [
    "source_name" => "",
    "reason_id" => '1',
    'frx_context' => '',
];

$datas = http_build_query($data);

//echo $datas;

$headers = [
    'accept: */*',
    'accept-language: ar,en-US;q=0.9,en;q=0.8',
    'content-type: application/x-www-form-urlencoded',
    'cookie: csrftoken=DqBQgbH1p7xEAaettRA0nmApvVJTi1mR; ig_did=C3F0FA00-E82D-41C4-99E9-19345C41EEF2; mid=X8DW0gALAAEmlgpqxmIc4sSTEXE3; ig_nrcb=1',
    'origin: https://www.instagram.com',
    'referer: https://www.instagram.com/',
    'sec-fetch-dest: empty',
    'sec-fetch-mode: cors',
    'sec-fetch-site: same-origin',
    'user-agent: Mozilla/5.0 (Linux; Android 6.0; Nexus 5 Build/MRA58N) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/86.0.4240.198 Mobile Safari/537.36',
    'x-csrftoken: DqBQgbH1p7xEAaettRA0nmApvVJTi1mR',
    'x-ig-app-id: 936619743392459',
    'x-ig-www-claim: 0',
    'x-instagram-ajax: bc3d5af829ea',
    'x-requested-with: XMLHttpRequest'
];
curl_setopt($ch, CURLOPT_URL, 'https://www.instagram.com/users/6828564602/report/');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $datas);
curl_setopt($ch, CURLOPT_COOKIEJAR, 'cookie.txt');
curl_setopt($ch, CURLOPT_COOKIEFILE, 'cookie.txt');


curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

$result = curl_exec($ch);
if (curl_errno($ch)) {
    echo 'Error:' . curl_error($ch);
} else {
    echo $result . "\n";
}
curl_close($ch);