If you want to extract highlighted text from PDF file as a plain text file, then this post covers some good free PDF Highlight Extractor software to do that.

PDF Replacer is a free software to find and replace text in bulk in PDF files. You can choose font types, remove text from PDF files using blank,etc.

There are several applications that enable you to replace text in PDF files. Adobe PDF files can be created and read on various computer media, such as mobile devices, PCs and Macs, as well as ...