I regularly read pdfs and annotate them. I use three types of annotations: highlight (yellow), underline (red) and note. With Okular I can select the type of annotation easily, that is with a keyboard shortcut.
From this answer I discovered Evince has Ctrl + H for highlight and S for Note, but there doesn't seem to be an easy way to underline text. The only way I found is to highlight text and then change annotation properties. Is there a way to add a shortcut to a custom annotation?