The Amish by nature are conservative, Christian, small business owners (i.e, farmers) & pacifists who'd normally align with Republicans.
However, to pick an example, when Obama ran against war-hawk McCain, many Amish were quite sympathetic with Obama.
Later they were as disappointed as others with Obama.
This year I'd guess, to a man or woman, the Amish like President Trump over his Democrat challengers (who?).
But even in Pennsylvania the Amish are a mere drop in the bucket -- less than one half of one percent of potential voters.
And the vast majority are not even registered to vote -- it's not forbidden to vote, but they like to stay out of politics as much as possible.
If some do vote, they would likely all vote Trump.
On the other hand the Amish, being good Christians, touch a lot of non-Amish lives in a positive way, and my guess is nearly all of those will vote Trump, thus multiplying the Amish influence by orders of magnitude.