Step: 1- Open settings.php file in sites/default and uncomment these lines

if (file_exists($app_root . '/' . $site_path . '/settings.local.php')) {
  include $app_root . '/' . $site_path . '/settings.local.php';
}

Step: 2 - Copy sites/example.settings.local.php to sites/default/settings.local.php:

Step: 3 -Open settings.local.php and Uncomment these lines

$settings['container_yamls'][] = DRUPAL_ROOT . '/sites/development.services.yml';

$settings['cache']['bins']['render'] = 'cache.backend.null';

$settings['cache']['bins']['dynamic_page_cache'] = 'cache.backend.null';

$settings['cache']['bins']['page'] = 'cache.backend.null';

Step: 3 - Open development.services.yml file add  below line of code  under parameters section

  twig.config:
    debug: true
    auto_reload: true
    cache: false

After added file look like this

# Local development services.
#
# To activate this feature, follow the instructions at the top of the
# 'example.settings.local.php' file, which sits next to this file.
parameters:
  http.response.debug_cacheability_headers: true
  twig.config:
    debug: true
    auto_reload: true
    cache: false
services:
  cache.backend.null:
    class: Drupal\Core\Cache\NullBackendFactory

Step: 4 - Rebuild cache

drush cr

or by visiting the following URL from your Drupal 8-9 website:

http://yoursite/core/rebuild.php