suffrage
universal suffrage
https://en.wikipedia.org/wiki/Universal_suffrage
https://www.wikidata.org/wiki/Q319891
Note that, in the 19th century, "universal suffrage" usually referred to universal manhood suffrage, before the women's suffrage movement.
The right to vote to all adult citizens, regardless of wealth, income, gender, social status, race, ethnicity, or any other restriction, subject only to relatively minor exceptions.
common suffrage of the common man
general suffrage
universal franchise