Drupal 8.x

but composer require drupal/smtp it doesn't work

[InvalidArgumentException]
  Could not find a matching version of package drupal/smtp. Check the package spelling, your version constraint and t
  hat the package is available in a stability which matches your minimum-stability (stable).

SMTP cannot be enabled because the PHPMailer library is missing.

I don't know how to deal with the problem.

I have built a basic entity in d8 using drupal console. I am then using a hook_form_alter to add some additional front-end fields to the form. These fields aren't functional on the back-end, but do some front-end stuff. 

Either way, I then made a hook_preprocess_form in my theme like this:

lms_preprocess_form(array &$variables) {

$variables['form'] = $variables['element'];

}

and I have a suggestions_form_alter() like this: