Modified Fields Front End

gf-update-dropdown-placeholder.php

add_filter( 'gform_pre_render', 'twentytwentyone_gf_add_placeholder' );
add_filter( 'gform_pre_validation', 'twentytwentyone_gf_add_placeholder' );
add_filter( 'gform_pre_submission_filter', 'twentytwentyone_gf_add_placeholder' );

function twentytwentyone_gf_add_placeholder( $form ) {

	if ( $form['id'] !== 1 ) {
		return;
	}

	$fields = $form['fields'];

	foreach( $fields as $field ) {

		if ( $field->type === 'select' && $field->label === 'State' ) {
			$field->placeholder = 'Select a State';
			$field->isRequired = true;
		}

		var_dump( $field );
	}

	return $form;
}