Hi,

Using through code you can disable the discount button in the POS

var screens = require('point_of_sale.screens');

    screens.ActionButtonWidget.include({
        button_click: function () {
            if (this.button_data.action === 'discount') {
                // Disable the action for the Discount button
                return;
            }
            this._super.apply(this, arguments);
        },
    });

Regards

You can disable the button element in HTML by adding the disabled attribute to the element. The disabled attribute is a boolean attribute that allows you to disable an element, making the element unusable from the browser.

Greetings,
Peter

Hi Ananda Khairum Nur Fajr, 

You can achieve mention feature by purchasing third party application from Odoo Apps Store. Many of them are free with this feature.