Need a freelancer for feature adding

Feature adding
"Invoice Ninja V4 New Addition:1A"
• PHP-61.6%
• JavaScript-30.6%
• Blade-6.5%
• Java-1.3%
New feature is required to comply with a situation of goods return.
Whenever a customer returns a product, we need to credit him.
The return might be full amount or partial. We need to have an option to choose from an existing invoice that was already created for the customer, and from that invoice, to have an additional option of “credit customer”.
The “credit customer“ option will reads the details of the original invoice, and open the invoice interface for editing.
The user (operator) can modify the invoice once user submitted. The total amount will be checked to verify is not above the original invoice value. If ok, the information will be stored as a "credit customer” invoice type.
The design will add on the header of the invoice the words-“credit invoice”.
From that point, whenever accessing the original invoice, we will have on the invoice menu additional option of “view credit invoice” in addition, on the main menu there will be a new section called “credit invoice” which will show all the credits invoices created. (For each one we will be able to click and watch without the option to edit) the credit invoice VAT is 0.
1. Go to https://github.com/invoiceninja/invoiceninja/releases/tag/v4.5.42
2. Download the source code
3. Install the system: https://docs.invoiceninja.com/install.html