I have some pdf content that was allowed to crawled by robots, and then after I changed it to premium feature. Now its already indexed by google and even I dont want google to stop it indexing but as I have set robots.txt for those pdf files they are showing the result in google search like:
A description for this result is not available because of this site's robots.txt
So My question is :
Can I set any relevant meta description for these PDF files?