simple_search_form.module

<?php

/**
 * @file
 * Contains simple_search_form module hooks.
 */

use Drupal\Core\Routing\RouteMatchInterface;

/**
 * Implements hook_help().
 */
function simple_search_form_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    // Main module help for the simple_search_form module.
    case 'help.page.simple_search_form':
      $output = '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('Module implements simple search form with input and submit button. It allows redirect user to a page with a GET parameter. Like: @example', ['@example' => '/some-site-page?myparam=sometext']);
      $output .= '<br>' . t('Use case: The parameter matches search API fulltext search or view exposed search filter.') . '</p>';
      return $output;

    default:
  }
}