FS36E - Fiscal Representation
The reason for needing a Fiscal Representative is that Finanças do not post correspondence outside of EU/Schengen and will need a representative here in Portugal who can receive your correspondence and make sure you comply with declarations, payments and any other instructions from the Finanças etc. This representative can be anyone who has a fiscal number in Portugal and who IS a Resident here or it can be an accountant/document agency/lawyer etc.