How to search for highlighted/underlined text on iPad?

Underlined bunch of things in several documents, now I'm not sure how to look for them. Isn't the sole purpose of highlighting stuff so that you can look back to it? Why would anyone highlight text if they can't search for it? Please let me know if this makes sense to anyone. If it does and Adobe can't do that, would anyone suggest an app that can do so?

Thanks a bunch in advance!