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Backtrace:

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Function: _error_handler

File: /home/intelgst/public_html/application/controllers/Category.php
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Function: require_once

A PHP Error was encountered

Severity: Warning

Message: Trying to access array offset on value of type null

Filename: views/view_header.php

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Backtrace:

File: /home/intelgst/public_html/application/views/view_header.php
Line: 162
Function: _error_handler

File: /home/intelgst/public_html/application/controllers/Category.php
Line: 55
Function: view

File: /home/intelgst/public_html/index.php
Line: 315
Function: require_once

A PHP Error was encountered

Severity: Warning

Message: Trying to access array offset on value of type null

Filename: views/view_header.php

Line Number: 163

Backtrace:

File: /home/intelgst/public_html/application/views/view_header.php
Line: 163
Function: _error_handler

File: /home/intelgst/public_html/application/controllers/Category.php
Line: 55
Function: view

File: /home/intelgst/public_html/index.php
Line: 315
Function: require_once

What is an Invoice? Importance, usage and elements.

An invoice is an essential document issued by a vendor to a purchaser, marking an official plea for payment following a transaction that includes goods or services. This pivotal document outlines the buyer's financial responsibilities to the vendor for acquiring certain goods or services. Typically, it enumerates items like the quantity of goods sold, their price per unit, descriptions of services provided, the aggregate amount due, payment stipulations, and the contact information of both the vendor and the purchaser.