Both Adobe Reader and Adobe Acrobat support optical character recognition in PDF files. OCR can recognize and convert characters such as English letters or Chinese symbols in images of typewritten text into machine-encoded text that you can manipulate. Adobe Reader allows subscribed users to use OCR to convert documents. Adobe Acrobat allows you to use text recognition with an optimization procedure.
Enable OCR in Adobe Reader
Open a PDF file and click Tools from the menu bar.
Click Change under the Export PDF section to recognize the text in the document.
Choose a language for the text in the document under Recognize Text In and click OK. For example, choose English (U.S.) if the text in the PDF file is in English. You can also disable the OCR feature in this window by toggling the Disable Text Recognition button.
Sign into your Adobe account in order to convert the PDF file to other document types such as Microsoft Word. Click Convert to export the file. Open the file in Word and edit it as you like.
Enable OCR in Adobe Acobat
Open a PDF file in Adobe Acrobat and click Tools on the menu bar.
Click Optimize Scanned PDF under Document Processing to set up optimization options for the PDF.
Check the Make Searchable (Apply OCR) check box under the OCR Options section. You can also change the settings under Optimization Options and Filters sections according to your preference. Click "Edit" under "OCR Options" to enter the language of the text in the document if it isn't English. Click OK. The text in the image can now be copied and pasted into a word processor to be edited.(see references 1, 2, 3)