Cannot find Highlight tool in Adobe Reader or Okular [closed]

I use Elementary OS Luna 64 bit. I'm trying to get the PDF annotating tools for highlighting text on PDF documents. I tried Adobe Reader and Okular. But both haven't that feature on my PC. But when I gogling I could see that both of those readers have that annotating feature. So what is the reason for that. Is that a missing of plug in or something?

Solution 1:

In Okular, you should press F6. then you will see a toolbar with different options for highlighting.

In old version it would appear like the following

In newer versions it will show as the following (screenshot from version 21.08.3):