I'm assuming that you are talking about the voter registration system in the United States.
The US voter registration system has gotten much simpler over the last couple of decades. It used to be that every state had their own system of registration. Different states made it more or less difficult to register. But in all states, you had to go to a certain place and fill out a form well in advance of an election.
Nowadays, there is one form that anyone in the US can use to register (I'm linking to it). There are still some differences between states as to who may register to vote and what the deadlines are, but everyone (except in New Hampshire and Wyoming) may use the national form and submit it by mail.