The following steps are used to add custom field offer in Opencart admin side(in add product section)
Free Download
http://www.opencart.com/index.php?route=extension/extension/download&extension_download_id=160521
Add a field named “Offer” to the product table in your MySql.
SQL CODE:
ALTER TABLE `product` ADD `offer` VARCHAR( 255 ) NOT NULL AFTER `model` ;
Usage;
<?php echo $text_offer; ?></span> <?php echo $offer; ?>
FILES CHANGED
admin->controller->catalog->product.php
->language->english->catalog->product.php
->model->catalog->product.php
->view->template->catalog->product_form.tpl
->catalog->controller->product->product.php
->language->english->product->product.php
->model->catalog->product.php