Quick Start Guide

Overview

This quick start guide will walk you through the essential steps to start using Simple Invoice, from your first login to generating your first professional invoice.

Before starting, ensure you have completed the Installation process and can access the login page.

Access the Login Page

Navigate to your Simple Invoice installation in your web browser:

http://localhost/simple_invoice/

Or your production domain:

https://yourdomain.com/

Use the default administrator credentials:

Username: admin
Password: admin

Security Alert: Change these default credentials immediately after your first login. Go to your user profile and update both the username and password.

The authentication system uses PHP’s password_verify() function for secure password hashing:

classes/Login.php

// Password verification from Login.php
if (password_verify($_POST['user_password'], $result_row->user_password_hash)) {
    // Write user data into PHP SESSION
    $_SESSION['user_id'] = $result_row->user_id;
    $_SESSION['user_name'] = $result_row->user_name;
    $_SESSION['user_email'] = $result_row->user_email;
    $_SESSION['user_login_status'] = 1;
}

Change Your Password

After logging in, immediately update your credentials:

Click on your username in the navigation bar
Select Profile or Settings
Update your password
Optionally change your username and email

The system uses bcrypt hashing for secure password storage.

Configure Your Company Profile

Before creating invoices, set up your company information:

Navigate to Company Profile

Access the company profile configuration page from the main navigation menu.

Enter Company Information

Fill in your business details:

Company Name (nombre_empresa)
Address (direccion)
City (ciudad)
Postal Code (codigo_postal)
State/Province (estado)
Phone (telefono)
Email (email)
Tax Rate (impuesto) - Enter as a percentage (e.g., 13 for 13%)
Currency - Select from 32+ supported currencies

View Company Profile Form Code

perfil.php

<input type="text" class="form-control" name="nombre_empresa" 
       value="<?php echo $nombre_empresa;?>" required>
<input type="text" class="form-control" name="direccion" 
       value="<?php echo $direccion;?>" required>
<input type="text" class="form-control" name="ciudad" 
       value="<?php echo $ciudad;?>" required>
<input type="number" class="form-control" name="impuesto" 
       value="<?php echo $impuesto;?>" required>

Upload Company Logo

Add your company logo to appear on invoices:

Supported formats: JPG, JPEG, PNG, GIF
Maximum file size: 1MB
Recommended size: 200x80 pixels

The logo will be stored in the img/ directory and referenced in the perfil table.

Save Configuration

Click Save Changes to store your company profile. This information will appear on all generated invoices.

Create Your First Client

Navigate to Clients

Click on Clients or Clientes in the main navigation menu.

Add New Client

Click the New Client button to open the client creation form.Enter the client information:

Client Name (nombre_cliente) - Required, must be unique
Phone (telefono_cliente) - Up to 30 characters
Email (email_cliente) - Up to 64 characters
Address (direccion_cliente)
Status (status_cliente) - Active (1) or Inactive (0)

View Client Creation Code

ajax/nuevo_cliente.php

$nombre_cliente = mysqli_real_escape_string($con, 
    (strip_tags($_POST["nombre_cliente"], ENT_QUOTES)));
$telefono_cliente = mysqli_real_escape_string($con, 
    (strip_tags($_POST["telefono_cliente"], ENT_QUOTES)));
$email_cliente = mysqli_real_escape_string($con, 
    (strip_tags($_POST["email_cliente"], ENT_QUOTES)));

$sql = "INSERT INTO clientes (nombre_cliente, telefono_cliente, 
        email_cliente, direccion_cliente, status_cliente, date_added) 
        VALUES ('$nombre_cliente','$telefono_cliente','$email_cliente',
        '$direccion_cliente','1', NOW())";

Save Client

Click Save to create the client record. The client will now be available when creating invoices with autocomplete functionality.

Create Your First Product

Navigate to Products

Click on Products or Productos in the main navigation.

Add New Product

Click New Product to open the product creation form.Enter product details:

Product Code (codigo_producto) - Required, unique identifier (up to 20 chars)
Product Name (nombre_producto) - Required (up to 255 chars)
Price (precio_producto) - Numeric value
Status - Active or Inactive

View Product Creation Code

ajax/nuevo_producto.php

$codigo_producto = mysqli_real_escape_string($con, 
    (strip_tags($_POST["codigo_producto"], ENT_QUOTES)));
$nombre_producto = mysqli_real_escape_string($con, 
    (strip_tags($_POST["nombre_producto"], ENT_QUOTES)));
$precio_producto = floatval($_POST['precio_producto']);

$sql = "INSERT INTO products (codigo_producto, nombre_producto, 
        status_producto, precio_producto, date_added) 
        VALUES ('$codigo_producto','$nombre_producto','1',
        '$precio_producto', NOW())";

Save Product

Click Save to add the product to your catalog. Products will be available for selection when creating invoices.

Generate Your First Invoice

Navigate to New Invoice

Click Invoices → New Invoice (or Nueva Factura) in the navigation.

Select Client

Start typing the client name in the Client field. The autocomplete feature will show matching clients:

nueva_factura.php

$("#nombre_cliente").autocomplete({
    source: "./ajax/autocomplete/clientes.php",
    minLength: 2,
    select: function(event, ui) {
        event.preventDefault();
        $('#id_cliente').val(ui.item.id_cliente);
        $('#nombre_cliente').val(ui.item.nombre_cliente);
        $('#tel1').val(ui.item.telefono_cliente);
        $('#mail').val(ui.item.email_cliente);
    }
});

Client phone and email will populate automatically.

Select Vendor and Payment Method

Vendor (id_vendedor) - Defaults to the logged-in user
Date (fecha) - Defaults to current date
Payment Method (condiciones):
- Efectivo (Cash)
- Cheque (Check)
- Transferencia bancaria (Bank Transfer)
- Crédito (Credit)

Add Products

Click Add Products to open the product search modal.

Search for products
Click on a product to add it to the invoice
Adjust quantity if needed
Products are temporarily stored in the tmp table during editing

The system automatically calculates:

Subtotal (sum of all line items)
Tax (based on company profile tax rate)
Total (subtotal + tax)

Review and Generate

Review the invoice details:

Verify all products and quantities
Check calculations
Confirm client information

Click Print or Generate to create the invoice.

View and Print Invoice PDF

After generating an invoice:

Invoice Saved to Database

The system saves the invoice to two tables:

facturas - Invoice header with client, date, total
detalle_factura - Line items with products and quantities

ajax/agregar_facturacion.php

$insert = mysqli_query($con, "INSERT INTO facturas (
    numero_factura, fecha_factura, id_cliente, id_vendedor, 
    condiciones, total_venta, estado_factura
) VALUES (
    '$numero_factura', NOW(), '$id_cliente', '$id_vendedor',
    '$condiciones', '$total_venta', 1
)");

Generate PDF

The system uses TCPDF to generate a professional PDF invoice:

Company logo (if uploaded)
Company information from profile
Client details
Product line items with prices
Subtotal, tax calculation, and total
Invoice number and date

pdf/documentos/factura_pdf.php

require_once(dirname(__FILE__).'/../html2pdf.class.php');
$html2pdf = new HTML2PDF('P', 'letter', 'en', array(0, 0, 0, 0));
$html2pdf->writeHTML($html, false);
$html2pdf->Output('Invoice_' . $numero_factura . '.pdf');

View or Download

The PDF opens in your browser. You can:

Print directly
Save to your computer
Email to the client

Multi-Currency Support

Simple Invoice supports 32+ currencies out of the box:

View Supported Currencies

Americas: USD, CAD, BRL, MXN, ARS, COP, GTQ
Europe: EUR, GBP, CHF, SEK, NOK, DKK
Asia: JPY, CNY, INR, PHP, THB, VND, IDR, MYR, SGD, HKD
Africa & Middle East: ZAR, EGP, NGN, AED, ILS
And more…

Each currency includes:

Symbol (e.g., $, €, £)
Precision (decimal places)
Thousand separator
Decimal separator
ISO code

To use a different currency:

Go to Company Profile
Select your preferred currency from the dropdown
All new invoices will use the selected currency format

Next Steps

Explore Features

Learn about user management, client operations, and advanced features.

Configure Settings

Customize database settings, company profile, and currency options.

API Reference

Explore AJAX endpoints for programmatic access.

Deploy to Production

Production deployment best practices and security hardening.

Pro Tip: Back up your database regularly, especially before major updates. The simple_invoice database contains all your business data including clients, products, and invoice history.

Get Started

Core Features

Configuration

Deployment

Overview

Configure Your Company Profile

Create Your First Client

Create Your First Product

Generate Your First Invoice

View and Print Invoice PDF

Multi-Currency Support

Next Steps

Explore Features

Configure Settings

API Reference

Deploy to Production

Build docs developers (and LLMs) love

Get Started

Core Features

Configuration

Deployment

​Overview

​First Login

​Configure Your Company Profile

​Create Your First Client

​Create Your First Product

​Generate Your First Invoice

​View and Print Invoice PDF

​Multi-Currency Support

​Next Steps

Explore Features

Configure Settings

API Reference

Deploy to Production

Build docs developers (and LLMs) love

Overview

First Login

Configure Your Company Profile

Create Your First Client

Create Your First Product

Generate Your First Invoice

View and Print Invoice PDF

Multi-Currency Support

Next Steps