route/web.php 

<?php

use Illuminate\Support\Facades\Route;
use Laravel\Fortify\Fortify;
use App\Models\User;

/*
|--------------------------------------------------------------------------
| Web Routes
|--------------------------------------------------------------------------
|
| Here is where you can register web routes for your application. These
| routes are loaded by the RouteServiceProvider within a group which
| contains the "web" middleware group. Now create something great!
|
*/

Route::get('json',function() {
  return response()->json(['name' => 'Virat Gandhi', 'state' => 'Gujarat']);
});

Route::get('json1',function() {
  return response()->json(User::all());
});

You can also put in route/api.php

this will prepend api to the url 

<?php

use Illuminate\Http\Request;
use Illuminate\Support\Facades\Route;
use App\Models\User;
/*
|--------------------------------------------------------------------------
| API Routes
|--------------------------------------------------------------------------
|
| Here is where you can register API routes for your application. These
| routes are loaded by the RouteServiceProvider within a group which
| is assigned the "api" middleware group. Enjoy building your API!
|
*/

Route::middleware('api')->get('/user', function (Request $request) {
  return response()->json(User::all());
});

If you use the auth api middleware it will require an api token

Route::middleware('auth:api')->get('/user', function (Request $request) {
  return response()->json(User::all());
});

Column not found: 1054 Unknown column 'api_token' in 'where clause' (SQL: select * from `users` where `api_token` = 

You will need to create a migration to add a api token column to users table

php artisan make:migration add_api_token_to_users_table

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class AddApiTokenToUsersTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
      Schema::table('users', function (Blueprint $table) {
        $table->string('api_token', 64);
      });
  }
    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::table('users', function (Blueprint $table) {
            //
            Schema::dropIfExists('api_token');
        });
    }
}