Install and Update Drupal 8 modules
To install a Drupal 8 module via Composer you need to run the following command
composer require drupal/module_name
For example to install the Drupal commerce module you need to run
composer require drupal/commerce
To update a Drupal 8 module you need to run the following command
composer update drupal/module_name --with-dependencies
For example to update the Mail system module you need to run
composer update drupal/mailsystem --with-dependencies
Thank you and looking forward to help you do more with Drupal