Can I use two different forms in one module?

I'm new to Drupal 8 and I was wondering if I can use two forms which are inside the Form folder(mymodule/src/Form/). The name of my forms are FormOne.php and FormTwo.php.

I can only display and use FormOne.php through my entire module.

I have researched it and can't find an answer.

Can you help me on displaying the second form?

You can create a custom Form in MyCustomFormA.php

<?php

namespace Drupal\MY_MODULE\Form;

use Drupal\Core\Form\FormBase;
use Drupal\Core\Form\FormStateInterface;

/**
 * Class MyCustomFormA.
 */
class MyCustomFormA extends FormBase {

  /**
   * {@inheritdoc}
   */
  public function getFormId() {
    return 'my_custom_form_a';
  }
.....
}

Same way you can create another Form in MyCustomFormB.php

<?php

namespace Drupal\MY_MODULE\Form;

use Drupal\Core\Form\FormBase;
use Drupal\Core\Form\FormStateInterface;

/**
 * Class MyCustomFormB.
 */
class MyCustomFormB extends FormBase {

  /**
   * {@inheritdoc}
   */
  public function getFormId() {
    return 'my_custom_form_b';
  }
....
}

In your MY_MODULE.routing.yml

MY_MODULE.my_custom_form_a:
  path: '/MY_MODULE/my_custom_form_a'
  defaults:
    _form: '\Drupal\MY_MODULE\Form\MyCustomFormA'
    _title: 'My Custom Form A Form'
  requirements:
    _permission: 'access content'
MY_MODULE.my_custom_form_b:
  path: '/MY_MODULE/my_custom_form_b'
  defaults:
    _form: '\Drupal\MY_MODULE\Form\MyCustomFormB'
    _title: 'My Custom Form B Form'

  requirements:
    _permission: 'access content'

Yes, you can define as many forms in a module as you need.

If you want to include two forms into one page, you can do so by using the form builder in your controller to call both forms and build a render array.

Instead of using _form in your *.routing.yml file, you would instead use _controller, and define a controller callback rather than a form callback. Your controller would then be something like this:

class ExampleController extends Drupal\Core\Controller\ControllerBase {

  function examplePageCallback() {
    // Note - you should use dependency injection to inject this service, 
    // rather than this method.
    $form_builder = \Drupal::service('form_builder');

    $return [
      'form_a' => $form_builder->getForm('Drupal\[MODULE]\Form\FormA'),
      'form_b' => $form_builder->getForm('Drupal\[MODULE]\Form\FormB'),
    ];
  }
}