How can I move a floating text or image with the video?
This is called Motion Tracking. You define a part on the head that will be tracked, and then have another object move relative to this position. 

I'm not sure this can be easily done with Premiere, as I've never done that, but it's a fairly standard procedure in After Effects. After Effects has a built-in tracking system, but there are also plugins like Mocha which offer the same features (and possibly a bit more).

There are hundreds of Motion Tracking tutorials online that explain how to do this, but looking for the term "Tracking" should get you started easily. For example, here's a tutorial for Premiere: