Here is a good place to start. I would also add to this about voting rights independent of political parties that rather certain people, like those pictured, not able to vote. Although this article is published 4 months ago, with recent news events of political expediency, a topical evergreen article.
Imagine a situation where you can’t prove to the world that you even exist. You are alive but you can’t prove your physical existence. Sounds horrible, Right! But according to the World Bank, there are more than a billion people in the world that have no means to prove their identity.
Without legal proof of your identity you officially have no rights. You can’t do many things like you can’t vote , you won’t have access to government services, you can’t drive etc. The people who come in this unverified category generally include refugees, the homeless, trafficked children and the people who have slipped in the society without developing any institutional affiliations.