AbanteCart is MVC and you need to update Model and controller to add new field.
It is pretty simple.
1. You add field in the product table. I assume this is already done.
2. Update model for product where field will be read and saved.
3. Update controller to pass HTML element with new field to view.
That is it for admin update. If you need to use (and I assume you do need) new field on storefront, you will need to update model and controller on storefront to get this data and display.
Below is the example, how you would this:
2. Locate /admin/model/catalog/product.php
Locate method
public function addProduct($data){
Add below line to SQL constructing:
supplier = '" . $this->db->escape($data['supplier']) . "',
3. Locate /admin/controller/pages/catalog/product.php
In function private _getForm add below code:
Add supplier to below fields array
$fields = array('product_category', ...
Add below code somewhere after line with $this->data['form']['fields']['data']['model'] :
$this->data['form']['fields']['data']['supplier'] = $form->getFieldHtml(array(
'type' => 'textarea',
'name' => 'supplier',
'value' => $this->data['supplier'],
'required' => false,
));
You are done.
FYI. To avoid programming to begin with you, can use product features that will add virtual field to products.
https://marketplace.abantecart.com/product-features-or-attributes?keyword=product&category_id=0