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 GET "https://api.dataforseo.com/v3/app_data/google/categories" \
--header "Authorization: Basic ${cred}"  \
--header "Content-Type: application/json" \

<?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/';
try {
	// Instead of 'login' and 'password' use your credentials from https://app.dataforseo.com/api-access
	$client = new RestClient($api_url, null, 'login', 'password');
} 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";
	exit();
}
try {
	// using this method you can get a list of categories
	// GET /v3/app_data/google/categories
	// in addition to 'google' you can also set other search engine
	// the full list of possible parameters is available in documentation
	$result = $client->get('/v3/app_data/google/categories');
	print_r($result);
	// do something with 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 client import RestClient
# You can download this file from here https://cdn.dataforseo.com/v3/examples/python/python_Client.zip
client = RestClient("login", "password")
# using this method you can get a list of categories
# GET /v3/app_data/google/categories
# in addition to 'google' you can also set other search engine
# the full list of possible parameters is available in documentation
response = client.get("/v3/app_data/google/categories")
# 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 axios = require('axios');

axios({
    method: 'get',
    url: 'https://api.dataforseo.com/v3/app_data/google/categories',
    auth: {
        username: 'login',
        password: 'password'
    },
    headers: {
        'content-type': 'application/json'
    }
}).then(function (response) {
    var result = response['data']['tasks'][0]['result'];
    // Result data
    console.log(result);
}).catch(function (error) {
    console.log(error);
});

using Newtonsoft.Json;
using System;
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 app_data_categories()
        {
            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"))) }
            };
            // using this method you can get a list of categories
            // GET /v3/app_data/google/categories
            // in addition to 'google' you can also set other search engine
            // the full list of possible parameters is available in documentation
            var response = await httpClient.GetAsync("/v3/app_data/google/categories");
            var result = JsonConvert.DeserializeObject<dynamic>(await response.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": "0.1.20220420",
    "status_code": 20000,
    "status_message": "Ok.",
    "time": "0.0557 sec.",
    "cost": 0,
    "tasks_count": 1,
    "tasks_error": 0,
    "tasks": [
        {
            "id": "04211836-2806-0435-0000-b2d10da73d5c",
            "status_code": 20000,
            "status_message": "Ok.",
            "time": "0.0000 sec.",
            "cost": 0,
            "result_count": 1,
            "path": [
                "v3",
                "app_data",
                "google",
                "categories"
            ],
            "data": {
                "api": "app_data",
                "function": "categories",
                "se": "google"
            },
            "result": [
                {
                    "categories": [
                        "art_and_design",
                        "auto_and_vehicles",
                        "beauty",
                        "books_and_reference",
                        "business",
                        "comics",
                        "communication",
                        "dating",
                        "education",
                        "entertainment",
                        "events",
                        "finance",
                        "food_and_drink",
                        "health_and_fitness",
                        "house_and_home",
                        "libraries_and_demo",
                        "lifestyle",
                        "maps_and_navigation",
                        "medical",
                        "music_and_audio",
                        "news_and_magazines",
                        "parenting",
                        "personalization",
                        "photography",
                        "productivity",
                        "shopping",
                        "social",
                        "sports",
                        "tools",
                        "travel_and_local",
                        "video_players",
                        "android_wear",
                        "watch_face",
                        "weather",
                        "game",
                        "game_action",
                        "game_adventure",
                        "game_arcade",
                        "game_board",
                        "game_card",
                        "game_casino",
                        "game_casual",
                        "game_educational",
                        "game_music",
                        "game_puzzle",
                        "game_racing",
                        "game_role_playing",
                        "game_simulation",
                        "game_sports",
                        "game_strategy",
                        "game_trivia",
                        "game_word",
                        "family"
                    ]
                }
            ]
        }
    ]
}