Is Foreign Income taxable In India

I was abroad from 2 years(so NRI currently), Now returned to India in April and working for Portuguese company individually and they need me to send invoices monthly for the payment.
Now this company need my VAT/fiscal number for taxation purpose. What should I provide here?

Also, what will the good way for me to save tax in India, Should I accept the amount individually or should I start a company and accept the amount on company’s account?

The Portuguese company will be paying my tax in Portugal. So do I also need to pay tax in India.

Thanks in advance.