You can easily copy content in Reader, unless the PDF author has applied security settings that disallow copying.
Copy text and images from PDFs
Copy an area of a PDF (Reader application only, not browser)
The Snapshot tool copies an area as an image that you can paste into other applications.
Choose Edit > Take a Snapshot.
Drag a rectangle around the area you want to copy, and then release the mouse button.
Press the Esc key to exit Snapshot mode.
In another application, choose Edit > Paste to paste the copied image.