yii2 ActiveForm numeric textfield

You can use ->textInput(['type' => 'number'] eg :

<?=$form->field($item, 'finalPrice', [
                                'options' => [
                                    'tag' => 'div',
                                    'class' => '',
                                ],
                                'template' => '<span class="col-md-2 col-lg-2"><label class="control-label">Final item price</label>{input}{error}</span>'
                            ])->textInput([
                                 'type' => 'number'
                            ])->label(false)?>

Try this . it worked for me

<?= $form->field($model, 'amount')->textInput(['type' => 'number']) ?>