Q:

Both is correct?  你认为如何 and 如何你认为

你认为如何 - More like a Chinese guy would talk like that. 
如何你认为 - Feels like the English sentence. * Like the sentence start with "What", "Which" etc. 
So both is correct? 
Especially to express:

What do you think...

A:

你认为如何
如何你认为

The first is correct but the second is wrong. 
However, even with this said, you may hear the second sentence from native speakers in casual conversations.  As I mentioned in this answer, some people tend to reverse orders while speaking.  For example "山东人我是".  But don't get me wrong: this sentence is not correct and you should not say the same.  However, just don't be surprised if you hear some native speakers make the same mistake.