The documents you have to supply are needed to prove to the Portuguese authorities – the SEF – that you meet the requirements of the Golden Residence Permit programme and that you are exactly the right kind of good citizen that they will be happy to welcome into their country.
These documents are: a passport, or another equivalent valid travel document, plus a visa (possibly a Schengen visa); and proof of your legal right to permanent residence in the country that issued the passport or travel document. Of course, when you have completed this fast track to your European Passport you will have free access to all 28 European countries in the Schengen area.
You will also be required to sign a document allowing the SEF to investigate your background and provide police clearance certificates from any country you have been resident in for more than one year.
And, for tax purposes, you will need to make a declaration that you have no outstanding debts owing to any Inland Revenue, Customs, or Social Security authorities.
So far so good. The third video in this group will tell you about the documents concerning the property requirements.