REGARDING NATURALIZACAO

Hi

can anyone explain me what exactly is the below doc

certidão ou inscrição consular emitida pela embaixada ou consulado no brasil, comprovando a correta grafia do nome interessado e de seus genitores

This is a Name Verification Certificate that is issued by the Embassy of your respective country.

It is issued in Portuguese and it pretty much states that the spelling of your name and your parents name along with your date birth that is printed on your CIE is accurate

do i need to pay embassy?
thanks in advance

That depends on your country's policies.   Since it's a consular service, chances are there will be a fee.  There usually is.
The nearest Indian Consulate is probably familiar with the form, and can help you.