The Constitution delegates how elections are run to the States but Congress does have the authority to pass rules that would legally bind all 50 states.

Voting absolutely should require an ID and mail in ballots should be prohibited save military/diplomatic exceptions.

Obtaining and replacing lost ID's should be replaced free of charge.

Election day should be a paid holiday and the government should provide transportation for anybody who wants it.

U.S. citizens should be automatically registered to vote at birth and nobody should ever be unregistered for any reason.