1) If the PDF file is the normal file, then please click
EDIT>Edit Text button, then click the text where you want to edit, you will get the blue box around it, and you can change the text in it directly.
2) If the PDF file is the scanned file, after openning it in the program, you will get the follwing yellow highlighted notice to ask you to
Perform OCR. So you can click this button to use it. If you get the message to ask you to purchase OCR, then please purchase it first. If you have already purchased the OCR, please install and register it.
After reinstalling and registering the OCR plugin, when you click the
Perform OCR button again, you will get the following window, click the
Change Language button to choose the correct language of your PDF content to perform.
After performing OCR, click the
EDIT>Edit Text button to edit the text then.