how to extract text from a PDF
A quick way to extract text from a PDF is to copy and paste information utilizing hotkeys such as [ctrl] + [c] to copy selected text and [ctrl] + [v]  to paste it in a text editor you wish to extract to. A way to automate this process is to use a programming language such as Python by importing Py2PDF and os and interacting with PDF objects in your filesystem.
What if it's a scan of a document and the text cannot be highlighted?
In this case there are many tools available that provide OCR (optical character recognition) techonlogy that transforms printed documents into digital image files. It’s a digital copy machine that uses automation to turn a scanned document into machine-readable PDF files you can edit and share. It should work well with good quality scanned documents.