>1. She turned her paper in to the teacher. 
vs. 
2. She turned her paper into the teacher. 
In the second sentence, the paper is transformed--poof!--into the teacher.  We've all heard the old joke about the magician who was so talented that he could drive down the street and turn into a gas station. Of course, if he just wanted to get gas somewhere, he would turn in to a gas station.

You're taking text links and making them hyperlinks. They're transforming. "Into" is correct.