Question on Barcodes (2018)

Question on barcodes.

Is there a central entity that tracks product barcodes sold in malls/groceries? Example may product ako na gusto ibenta sa market, how will I know that my barcode is unique for my product. Given na maraming free barcode generator online, for this use-case, is it mandatory that I register/buy my barcode somewhere for legal purposes?

I saw the website barcode.ph and would want to ask if...

1) legal entity ba sila?
2) mandatory that i go through them? If not, what is actually the mandatory steps I need to do.

Thanks in advance! 😊