For those of you ladies and gents who may be interested, just sharing the process steps for obtaining the Social Security declaration of negative debt or non-existence of a record for GV (in my case it was the latter). This method works if you are physically present in Portugal.
What you need to do it google up the nearest Segurança Social office and just turn up with no prior appointment.
There will be a machine printing out queue tickets, I was asked by their staff to press the top option and then on the next screen the top option again.
When I got to the counter I just explained what I needed and showed the GV requirements printout from the SEF website in Portuguese.
In a few minutes I received the declaration signed and stamped.
Just be sure to check it before you leave as mine had a spelling error, which they corrected and reprinted.
Hope this helps.
Or if you are outside Portugal . Follow the instructions here.
Thanks JP, but this one is for the Tax Authority. And yes, it can be obtained online.
But Social Security is a separate organization and will issue its own declaration.
I assume the one from Social Security is needed if you already live in Portugal ?
As far as the SEF requirements document goes, it is required from any GV applicant regardless of where they reside:
"Evidence of the tax obligations duly filled in by means of submitting the negative debt
declaration issued, up to 45 days maximum in advance, by the Tax and Customs Authority and
the Social Security or, if not feasible, a declaration stating the non-existence of a record within
these entities"