It depends on the placement in the sense that you obviously wouldn't say' Said Joe, "Hi."'
You would say 'Joe said "Hi."' But even then, that's not a common phrasing of that sentence.
The most common way of seeing this written would be.
"Hi," said Joe.
'said Joe' is generally preferred structurally because 'joe said' is more commonly used in children's books and so it's a bit of a mark of a writer writing for younger people to use the latter.
On the other hand, neither one is actually incorrect, it's more just a matter of both placement and writing style.
Hope this is helpful.