how to convert "img file to searchable pdf" in c# windows application ?

Ok, this answer is not going to give you any ready-made code or solution because the question you have asked itself is not complete.

Next, when your boss gives you a task he expects you to complete and not someone on CodeProject. Of course, the community is there to help you but that’s only to help and not to do your work.

If you don’t have a clarity on what/how it needs to be done, go back and ask your boss. That’s what he is paid for i.e. to help you get work done.

On the other hand, if you don’t express to him what your limitations are, he would never know what he can expect from you or in which area you need further training.

So, for your long-long career ahead, please be honest with your boss. It will really help you and of course your boss as well to deliver the things which you have agreed with your client.

What I would suggest now is to go back, get it clarified and try on your own. Show us what you have tried and if still have problems then ask a clear question. I am sure someone would be more than willing to help you.