When you register to vote online, you are required to enter you Social Security Number and Date of Birth in order to proceed. The portal confirms your ID by matching with Driver’s License records.
Free ID
The state will make you a free ID card. You get it where you can get a driver’s license, and drive.ky.gov is where you can find the nearest state office for that.
If you do not have (or do not want to provide) a Social Security Number, you can still register in person at your county clerk office or by mail, but you must provide your date of birth and signature.