Compare and Highlight and comment

Hi,
I have a pdf with content and input parameters will be “BeforeParagraph” and “AfterParagraph”.
In pdf i need to look for content which i received in “BeforeParagraph” parameter. Once i find paragraph i need to highlight the difference from “AfterParagraph” and “BeforeParagraph” in pdf and add comment at exact location on what is changed.
Document Type: PDF
Technology : .net
Really appreciate the help to start with

@tejkamalleo

We suggest you please read the following articles.
Search and Get Text from Pages of PDF
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Could you please attach your input and expected output PDF files here for our reference? We will then provide you more information about your query.