How to upgrade laravel version from 6 to 10

hello guys iam using an online student exam application and i have done that application 3 years back while developing the version is Laravel Framework 6.20.44 currently i need to update that version in live cpanel. currenlty my cpanel php version is 7.4

First let me post my config/app. php

 'aliases' => [

        'App' => Illuminate\Support\Facades\App::class,
        'Arr' => Illuminate\Support\Arr::class,
        'Artisan' => Illuminate\Support\Facades\Artisan::class,
        'Auth' => Illuminate\Support\Facades\Auth::class,
        'Blade' => Illuminate\Support\Facades\Blade::class,
        'Broadcast' => Illuminate\Support\Facades\Broadcast::class,
        'Bus' => Illuminate\Support\Facades\Bus::class,
        'Cache' => Illuminate\Support\Facades\Cache::class,
        'Config' => Illuminate\Support\Facades\Config::class,
        'Cookie' => Illuminate\Support\Facades\Cookie::class,
        'Crypt' => Illuminate\Support\Facades\Crypt::class,
        'DB' => Illuminate\Support\Facades\DB::class,
        'Eloquent' => Illuminate\Database\Eloquent\Model::class,
        'Event' => Illuminate\Support\Facades\Event::class,
        'File' => Illuminate\Support\Facades\File::class,
        'Gate' => Illuminate\Support\Facades\Gate::class,
        'Hash' => Illuminate\Support\Facades\Hash::class,
        'Lang' => Illuminate\Support\Facades\Lang::class,
        'Log' => Illuminate\Support\Facades\Log::class,
        'Mail' => Illuminate\Support\Facades\Mail::class,
        'Notification' => Illuminate\Support\Facades\Notification::class,
        'Password' => Illuminate\Support\Facades\Password::class,
        'Queue' => Illuminate\Support\Facades\Queue::class,
        'Redirect' => Illuminate\Support\Facades\Redirect::class,
        'Redis' => Illuminate\Support\Facades\Redis::class,
        'Request' => Illuminate\Support\Facades\Request::class,
        'Response' => Illuminate\Support\Facades\Response::class,
        'Route' => Illuminate\Support\Facades\Route::class,
        'Schema' => Illuminate\Support\Facades\Schema::class,
        'Session' => Illuminate\Support\Facades\Session::class,
        'Storage' => Illuminate\Support\Facades\Storage::class,
        'Str' => Illuminate\Support\Str::class,
        'URL' => Illuminate\Support\Facades\URL::class,
        'Validator' => Illuminate\Support\Facades\Validator::class,
        'View' => Illuminate\Support\Facades\View::class,

        // Input 
        'Input' => Illuminate\Support\Facades\Input::class,
        
        //sweet alert
        'Alert' => UxWeb\SweetAlert\SweetAlert::class,
        //Pdf
        'PDF' => Barryvdh\DomPDF\Facade::class,
        //Image Upload
        'Image' => Intervention\Image\Facades\Image::class,
        'DataTables' => Yajra\DataTables\Facades\DataTables::class,
        'Alert' => RealRashid\SweetAlert\Facades\Alert::class,
        
    ],

this is my composer.json

{
    "name": "laravel/laravel",
    "type": "project",
    "description": "The Laravel Framework.",
    "keywords": [
        "framework",
        "laravel"
    ],
    "license": "MIT",
    "require": {
        "php": "^7.2",
        "barryvdh/laravel-dompdf": "^0.8.6",
        "fideloper/proxy": "^4.0",
        "filp/whoops": "^2.7",
        "intervention/image": "^2.5",
        "laravel/framework": "^6.2",
        "laravel/tinker": "^2.0",
        "realrashid/sweet-alert": "^3.1",
        "spatie/laravel-permission": "^3.11",
        "uxweb/sweet-alert": "^2.0",
        "yajra/laravel-datatables-buttons": "^4.0",
        "yajra/laravel-datatables-editor": "^1.19",
        "yajra/laravel-datatables-fractal": "^1.5",
        "yajra/laravel-datatables-html": "^4.22",
        "yajra/laravel-datatables-oracle": "^9.8"
    },
    "require-dev": {
        "facade/ignition": "^1.4",
        "fzaninotto/faker": "^1.4",
        "laravel/ui": "^1.0",
        "mockery/mockery": "^1.0",
        "nunomaduro/collision": "^3.0",
        "phpunit/phpunit": "^8.0"
    },
    "config": {
        "optimize-autoloader": true,
        "preferred-install": "dist",
        "sort-packages": true
    },
    "extra": {
        "laravel": {
            "dont-discover": []
        }
    },
    "autoload": {
        "psr-4": {
            "App\": "app/"
        },
        "classmap": [
            "database/seeds",
            "database/factories"
        ]
    },
    "autoload-dev": {
        "psr-4": {
            "Tests\": "tests/"
        }
    },
    "minimum-stability": "dev",
    "prefer-stable": true,
    "scripts": {
        "post-autoload-dump": [
            "Illuminate\Foundation\ComposerScripts::postAutoloadDump",
            "@php artisan package:discover --ansi"
        ],
        "post-root-package-install": [
            "@php -r \"file_exists('.env') || copy('.env.example', '.env');\""
        ],
        "post-create-project-cmd": [
            "@php artisan key:generate --ansi"
        ]
    }
}

and my file structure in app folder itself all my model files will be present.

Now how i need to upgrade this application. what i did is just gave composer update but i think no change when i check again php artisan --version it showing the old 6.20 version only. what are the changes i need to do to upgrade my laravel application to current version kindly some one help. updating php version in the cpanel that i can do it. but this laravel version how to upgrade?