Article 56 of the 1995 Constitution of Azerbaijan established the right to vote for citizens.

References:

“Azerbaijan 1995 (rev. 2016).” Constitute. https://www.constituteproject.org/constitution/Azerbaijan_2016

Blaustein, Albert P., and Gisbert H. Flanz. Constitutions of the Countries of the World; a Series of Updated Texts, Constitutional Chronologies and Annotated Bibliographies. "Azerbaijan Republic, Booklet 2, 1996" Permanent ed. Dobbs Ferry, N.Y: Oceana Publications, 1971.