The order titled “Preserving and Protecting the Integrity of American Elections” requires voters to show proof of citizenship and limits when states can receive mail-in ballots. 
It is unclear how enforceable the order is, given US states have wide legal leeway to determine how they run their elections. It is expected to be challenged in court. The order calls on states to cooperate or risk losing access to federal funding.
The legality of the order is expected to be challenged in court.
Presidential Executive Order: Overhaul Elections