How is the national electoral register created?

Republic of Austria, ODIHR Needs Assessment Mission Report, Early Parliamentary Elections, 29 September 2019, accessed 9 September 2019

“Voters are automatically included in the voter lists by municipal authorities according to their place of main residence, except citizens living abroad who have to register actively. Several ODIHR NAM interlocutors noted that the new Central Voter Register, which came into effect on 1 January 2018, allowed for improving data quality, centralized cleansing of duplicate records and effective data processing at local level. No concerns were expressed regarding the overall accuracy and inclusiveness of the voter lists.”