I'm new to the software, so please bear with me

I have a bunch of images containing white paper on a black background(which is full of little white dots). I need to get rid of this this background, while at the same time resizing the image so that only the white paper is shown.
Is there a particular action flow that you guys reccomend? Crop maybe?
Here's a sample of how it is and how it should become.
Thanks for the help!