_form (example)

<?php

use app\models\Contactperson;
use yii\helpers\Html;
use yii\bootstrap4\ActiveForm;
use yii\web\View;

/* @var $this yii\web\View */
/* @var $model app\models\Contactperson */
/* @var $form yii\bootstrap4\ActiveForm */

\app\assets\AdminLTE3FormElementsAsset::register($this);
$bsCustomFileInitJs = 'bsCustomFileInput.init()';
$this->registerJs($bsCustomFileInitJs, \yii\web\View::POS_READY);
?>

<div class="row">
    <div class="col-12 p-0">
        <?php $form = ActiveForm::begin([

        ]); ?>
        <div class="contactperson-form-header container-fluid">
            <div class="row bg-dark align-items-center px-2">
                <div class="col-auto py-4 px-3">

                </div>
                <div class="col">
                    <h1><?= Html::encode($this->title) ?></h1>
                </div>
                <div class="col d-flex justify-content-end align-self-end">
                    <div class="form-group">
                        <?= Html::submitButton('<i class="fa fa-save"></i> Save', ['class' => 'btn btn-primary']) ?>
                    </div>
                </div>
            </div>
        </div>
        <div class="contactperson-form-body container p-3">
            <div class="row">
                <div class="col">
                    <div class="card">
                        <div class="card-body">
                            <div class="row">
                                <div class="col">
                                    <label>Avatar</label>
                                    <div class="row">
                                        <div class="col-auto">
                                            <figure class="figure">
                                                <?= Html::img($model->getImagePath(),['class'=>' figure-img img-fluid ']); ?>
                                            </figure>
                                        </div>
                                        <div class="col">
                                            <div class="row">
                                                <div class="col-auto">
                                                    <?=
                                                    $form->field($model, "image", [
                                                        'template'=>"<div class=\"custom-file\">{input}\n{error}<label for=\"customFile\" class=\"custom-file-label\">Datei auswählen...</label></div>",
                                                        'validateOnBlur' => false
                                                    ])->fileInput(['class'=>'custom-file-input', 'id'=>'customFile']);
                                                    ?>
                                                </div>
                                                <div class="col">
                                                    <?= Html::submitButton('Upload', ['class' => 'btn btn-default', 'name'=>'upload', 'value'=>'true']) ?>
                                                </div>
                                            </div>
                                        </div>
                                    </div>

                                    <div class="form-group field-contactperson-gender">
                                        <label class="control-label" for="contactperson-gender">Salutation</label>
                                        <input type="hidden" name="Contactperson[gender]" value="">
                                        <div class="">
                                            <div id="contactperson-gender" class="btn-group btn-group-toggle" data-toggle="buttons">
                                                <label class="btn btn-outline-secondary active">
                                                    <input type="radio" name="Contactperson[salutation]" value="0" id="option1" autocomplete="off" checked=""> No
                                                </label>
                                                <label class="btn btn-outline-secondary">
                                                    <input type="radio" name="Contactperson[salutation]" value="1" id="option2" autocomplete="off"> Sir
                                                </label>
                                                <label class="btn btn-outline-secondary">
                                                    <input type="radio" name="Contactperson[salutation]" value="2" id="option3" autocomplete="off"> Madam
                                                </label>
                                            </div>
                                        </div>
                                        <div class="help-block"></div>
                                    </div>

                                    <?= $form->field($model, 'name')->textInput(['maxlength' => true, 'placeholder'=>'']) ?>

                                    <?= $form->field($model, 'role')->textInput(['maxlength' => true, 'placeholder'=>'']) ?>

                                </div>
                                <div class="col">
                                    <?= $form->field($model, 'email')->textInput(['maxlength' => true, 'placeholder'=>'']) ?>

                                    <?= $form->field($model, 'phone')->textInput(['maxlength' => true, 'placeholder'=>'']) ?>

                                    <?= $form->field($model, 'phone_mobile')->textInput(['maxlength' => true, 'placeholder'=>'']) ?>
                                </div>
                            </div>
                        </div>
                    </div>
                </div>
            </div>
        </div>
        <?php ActiveForm::end(); ?>
    </div>
</div>