If you are using this plugin with WooCommerce you will see user will able to automatically login just after registrations, so you can stop them to auto login to force verify account first.

you need to use this code on your theme functions.php file.

add_filter( 'woocommerce_registration_redirect', 'user_verification_woocommerce_registration_redirect', 10, 1 );

function user_verification_woocommerce_registration_redirect(){

  if ( is_user_logged_in() ) {
    $current_user = wp_get_current_user();
    $user_id = $current_user->ID;
    $approved_status = get_user_meta($user_id, 'user_activation_status', true);
    //if the user hasn't been approved destroy the cookie to kill the session and log them out
    if ( $approved_status == 1 ){

      return get_permalink(wc_get_page_id('myaccount'));
      return get_permalink(wc_get_page_id('myaccount')) . "?approved=false";

function registration_message(){

  $not_approved_message = '<p class="registration">Send in your registration application today!<br /> NOTE: Your account will be held for moderation and you will be unable to login until it is approved.</p>';
  if( isset($_REQUEST['approved']) ){

    $approved = sanitize_text_field($_REQUEST['approved']);
    if ($approved == 'false')  echo '<p class="registration successful">Registration successful! You will be notified upon approval of your account.</p>';
    else echo $not_approved_message;
  else echo $not_approved_message;

add_action('woocommerce_before_customer_login_form', 'registration_message', 2);