This extension is a wrapper over Spire.PDF C# library to extract text from PDF documents. 

https://www.e-iceblue.com/Introduce/pdf-for-net-introduce.html

Spire.PDF 

It is totally free without any warning message for your commercial and personal use. Free version is limited to 10 pages of PDF. This limitation is enforced during loading and creating files. When converting PDF to Image, the first 3 pages of PDF files will be converted to Image format successfully.

If your requirements exceed the limitation, please use the commercial edition. 

The extension has methods 

1) PDF_TextExtraction_LoadPDF 

  Method to load the PDF file contents.
This method should be called first before calling any other method.

2) PDF_TextExtraction_GetPageCount

This method returns the page count in the loaded pdf document.
Returns -1 if the document is not loaded.
Returns the count of the pages in the document

3) PDF_TextExtraction_GetAllText

Get the entire text of PDF file

4) PDF_TextExtraction_GetTextAtPageNo

Get Text for a particular page number.