How is the national electoral register created?

Guatemala, International Foundation for Electoral Systems, '2019 Presidential Election Runoff', Frequently Asked Questions, How do citizens register to vote?, accessed 14 August 2019

Registered Guatemalans over the age of 18 are eligible to vote. As of March 2019, there are 8,149,7937 registered or “empowered” voters, as they are referred to in Guatemala, including 4,386,509 women and 3,763,284 men. The number increased by 592,920 from the 7,556,873 (4,074,450 women and3,482,423 men) who were registered in the 2015 elections. The Supreme Electoral Tribunal has a website to facilitate the registration process. The deadline for voter registration in these elections was March 17.