I gave you a whole book. Start reading! As I stated, there are numerous studies. Some funded by groups that want to increase voter ID laws. What is the purpose and rationale behind voter ID laws? Voter fraud is not a thing. Which groups are less likely to have them? Which types of IDs are accepted and selectively not accepted? The legislatures creating them are headed by Republicans. Many of them are states with a history of voter suppression. That says it all.