read description .....php code or custom script call --1 -- 2

I want to create a shrot code or php code that will check the financial office of my country and will call to check if the customer enters a vat number for VAT exemption ..shops that use this are the following
https://www.plaisio.gr/taxexemptioncheck
https://www.aade.gr/en/service-article-39a-par5-circular-11502992017 this is service to work
https://www.you.gr/special-pages/elenchos-afm

my store is woocomrce platform ..I wrote a code but it doesn't work