Hello skdkarthick,
Get Text is only a valid option for Windows elements that have a text attribute, it is not a relevant option for regions.
If you are going to use regions you should first complete the Surface Automation training which will teach you about the options available to you for reading text from regions.
For PDF's I think you will have a problem with the font, scale, and reliable position, of what you are trying to read from - have you read the guide in the learning area of the portal specifically related to interfacing with PDF documents?