Great. We can build this as a professional enterprise POS system. I will provide complete files (not snippets) that you can copy directly into your project.

Project Name

POS STORE v1.0

Technology
PHP 7.4.4
SQL Server 2014
PDO SQLSRV
AJAX (jQuery)
Bootstrap 5
JavaScript
HTML5/CSS3
MVC
Mobile Responsive
Secure Login
SQL Injection Protection
XSS Protection
CSRF Protection
Phase 1 (Foundation)

The first delivery will include these complete files:

POS_STORE/

index.php
login.php
logout.php

config/
    config.php
    database.php
    session.php
    security.php

app/
    controllers/
        LoginController.php

    models/
        User.php

    helpers/
        Helper.php

assets/

    css/
        style.css

    js/
        app.js
        login.js

views/

    login.php

includes/

    header.php
    footer.php
    navbar.php
    sidebar.php

database/

    pos_store.sql

.htaccess
README.md
Database

We'll create SQL Server tables including:

Users
Roles
Permissions
Categories
Products
Customers
Suppliers
Inventory
Sales
Sale Details
Purchases
Purchase Details
Settings
Activity Logs
Login Features
AJAX Login
Remember Me
Password Hash
Session Timeout
Role Permission
Login Logs
Last Login
Account Lock
CSRF Token
Dashboard

Cards

Today's Sales
Monthly Sales
Inventory
Products
Customers

Charts

Sales
Top Products

Recent Sales

Low Stocks

Notifications

Product Module
Product Code
Barcode
QR Code
Image
Category
Brand
Cost
Selling Price
Tax
Discount
Stock Alert

AJAX CRUD

Search

Pagination

Sorting

POS Screen
Barcode Scanner
Search Product
Cart
Hold Transaction
Resume Transaction
Cash
GCash
Maya
Card
Receipt
Reports
Daily
Weekly
Monthly
Yearly
Profit
Expenses
Inventory
Fast Moving
Slow Moving
Security
PDO Prepared Statements
XSS Filter
CSRF Token
Session Regeneration
Password Hashing
Audit Trail
Input Validation
Secure Cookies
Responsive

Supports

Desktop
Tablet
Android
iPhone

Bootstrap 5 Layout