Buzz
Certainly, copying PDF documents won't grant you the ability to read or edit PDF files as desired unless you have specialized PDF editing software such as Foxit Reader or the premium version of Adobe Reader, which unlocks advanced features for editing, cutting, and pasting PDF files more conveniently.
Nevertheless, the free versions of Adobe Reader or Foxit Reader, along with tools like Solid Convert PDF or Free PDF to Word Converter, now offer ample features for note-taking, copying, and more, catering well to users' needs.
Wishing you, Thiên, and all others success!
