customize 4 elements, pay 400 to 500 usd

i need adding 4 elements: (1) Modify the templates of sales invoices as data formats and taxes in my country. Also in the purchasing data. (2) one of those fields is generating sales invoices with security code algorithm and a QR code (3) Export txt files as standard purchases and sales fields. (4) import txt files with similar fields to generate massive default accounting entries. Whether purchase invoices and sales invoices.

I pay 400 to 500 usd. I would appreciate if the programmer speaks Spanish.

please here the link of freelancer

https://www.freelancer.com/projects/PHP-Javascript/Personalizar-software-contable-basado.html