How is the national electoral register created?

Sweden, Election Act (2005: 837; last amended in 2021), Chapter 5. Electoral rolls and voting cards, accessed 12 September 2022

Section 1. In connection with elections the central election authority shall for each electoral district prepare a list of those who are entitled to vote in the election (electoral roll).

The electoral rolls shall be based on the information that, 30 days prior to the election day, is contained in the population registration database in accordance with the Act on the Processing of Personal Data in the Swedish Tax Agency’s Population Registration Activities (2001:182) and in the land register in accordance with the Land Registration Act (2000:224).