Good question... I googled “do Amish vote” and the answer is that of course they legally may, but they are not all united on one philosophy about whether to do it.
How the Amish, and other Christians, can think that sitting on the sidelines while neo-Nazis—i.e., DEMOCRATS—take over the country and murder 60 million babies, etc., is “Christian” behavior is beyond me. It was decades after Jerry Falwell formed the Moral Majority that I learned that most evangelicals don’t vote.