Instead of ‘login’ and ‘password’ use your credentials from https://app.dataforseo.com/api-access

# Instead of 'login' and 'password' use your credentials from https://app.dataforseo.com/api-access
login="login"
password="password"
cred="$(printf ${login}:${password} | base64)"
curl --location --request POST "https://api.dataforseo.com/v3/on_page/page_screenshot" \
--header "Authorization: Basic ${cred}" \
--header "Content-Type: application/json" \
--data-raw '[
  {
    "url": "https://dataforseo.com/apis"
  }
]'

<?php
// You can download this file from here https://cdn.dataforseo.com/v3/examples/php/php_RestClient.zip
require('RestClient.php');
$api_url = 'https://api.dataforseo.com/';
// Instead of 'login' and 'password' use your credentials from https://app.dataforseo.com/api-access
$client = new RestClient($api_url, null, 'login', 'password');

$post_array = array();
// simple way to get a result
$post_array[] = array(
   "url" => "https://dataforseo.com/apis"
);
try {
   // POST /v3/on_page/page_screenshot
   // the full list of possible parameters is available in documentation
   $result = $client->post('/v3/on_page/page_screenshot', $post_array);
   print_r($result);
   // do something with post result
} catch (RestClientException $e) {
   echo "n";
   print "HTTP code: {$e->getHttpCode()}n";
   print "Error code: {$e->getCode()}n";
   print "Message: {$e->getMessage()}n";
   print  $e->getTraceAsString();
   echo "n";
}

$client = null;
?>

from random import Random
from client import RestClient
# You can download this file from here https://api.dataforseo.com/v3/_examples/python/_python_Client.zip
client = RestClient("login", "password")

post_data = dict()
# simple way to get a result
post_data[len(post_data)] = dict(
    url="https://dataforseo.com/apis"
)
# POST /v3/on_page/page_screenshot
# the full list of possible parameters is available in documentation
response = client.post("/v3/on_page/page_screenshot", post_data)
# you can find the full list of the response codes here https://docs.dataforseo.com/v3/appendix/errors
if response["status_code"] == 20000:
    print(response)
    # do something with result
else:
    print("error. Code: %d Message: %s" % (response["status_code"], response["status_message"]))

const post_array = [];

post_array.push({
  "url": "https://dataforseo.com/apis"
});

const axios = require('axios');

axios({
  method: 'post',
  url: 'https://api.dataforseo.com/v3/on_page/page_screenshot',
  auth: {
    username: 'login',
    password: 'password'
  },
  data: post_array,
  headers: {
    'content-type': 'application/json'
  }
}).then(function (response) {
  var result = response['data']['tasks'];
  // Result data
  console.log(result);
}).catch(function (error) {
  console.log(error);
});

using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Threading.Tasks;

namespace DataForSeoDemos
{
    public static partial class Demos
    {
        public static async Task on_page_page_screenshot()
        {
            var httpClient = new HttpClient
            {
                BaseAddress = new Uri("https://api.dataforseo.com/"),
                // Instead of 'login' and 'password' use your credentials from https://app.dataforseo.com/api-access
                DefaultRequestHeaders = { Authorization = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(Encoding.ASCII.GetBytes("login:password"))) }
            };
            var postData = new List<object>();
            // simple way to get a result
            postData.Add(new
            {
                url = "https://dataforseo.com/apis"
            });
            // POST /v3/on_page/page_screenshot
            // the full list of possible parameters is available in documentation
            var taskPostResponse = await httpClient.PostAsync("/v3/on_page/page_screenshot", new StringContent(JsonConvert.SerializeObject(postData)));
            var result = JsonConvert.DeserializeObject<dynamic>(await taskPostResponse.Content.ReadAsStringAsync());
            // you can find the full list of the response codes here https://docs.dataforseo.com/v3/appendix/errors
            if (result.status_code == 20000)
            {
                // do something with result
                Console.WriteLine(result);
            }
            else
                Console.WriteLine($"error. Code: {result.status_code} Message: {result.status_message}");
        }
    }
}

The above command returns JSON structured like this:

{
    "version": "0.1.20220428",
    "status_code": 20000,
    "status_message": "Ok.",
    "time": "6.3639 sec.",
    "cost": 0.004,
    "tasks_count": 1,
    "tasks_error": 0,
    "tasks": [
        {
            "id": "05061850-1535-0444-0000-698f746278b6",
            "status_code": 20000,
            "status_message": "Ok.",
            "time": "6.3053 sec.",
            "cost": 0.004,
            "result_count": 1,
            "path": [
                "v3",
                "on_page",
                "page_screenshot"
            ],
            "data": {
                "api": "on_page",
                "function": "page_screenshot",
                "url": "https://dataforseo.com/apis"
            },
            "result": [
                {
                    "crawl_progress": "finished",
                    "error_message": null,
                    "items_count": 1,
                    "items": [
                        {
                            "image": "https://api.dataforseo.com/cdn/screenshot/05061850-1535-0444-0000-698f746278b6"
                        }
                    ]
                }
            ]
        }
    ]
}