How come in this phrase "va a estudiar ella en la biblioteca hoy?" has ella AFTER the word estudiar? Couldn't I just put 'ella' before va as well, like as in "ella va a estudiar en la biblioteca hoy?" I know spanish is flexible so I was wondering if it is grammatically correct to write it the second way, and I also want to know WHY "ella" was put after the action.

because its a question and not a stetement

Explanation:

yes you could put ella before va but that would make it a statement. So in order for the sentance to be a question they put ella after estudiar.

It is correct to say that, I think it is even more correct/native to say the second phrase.

And the second question, I don't really know it. I'm spanish, but I would never say '' va a estudiar ella en a biblioteca hoy'', I would say '' ella a a estudiar hoy en la biblioteca''.