The title makes sense if you imagine they skipped "that" before France:
Emmanuel Macron squirms as Donald Trump orders that France leaves
The court ordered that he leaves Antigua on Thursday. (Jamaica Observer)
President Donald Trump to visit Iowa.
is simply a short form of
President Donald Trump is going to visit Iowa
President Donald Trump is expected to visit Iowa
with the omitted words implied and understood. Note that in news stories, particularly in headlines, brevity is particularly desired, and so customary omissions have developed which are ...
Your embedded question (involving sentences like "Trump to visit Iowa in June") are examples of "journalese"—a writing style that is featured in news writing and, especially, headlines, where it is sometimes called "headlinese."
Native readers of such a headline will complete it mentally in a heartbeat, but you may be able to understand it better by ...