Annotate a PDF?

Quick question: Can someone of you annotate PDF files (write and/or draw on them)?

I tried the Documents app but when I press the pencil and draw, nothing happens.
I also searched in J.Store/Storeman/Chum with keywords like “pdf” and/or “annotate” without success.

For me the pencil just highlights existing text in yellow

Xperia X / SFOS
I can highlight and write a note too.

Right, for a note I have to tap the bubble

Ok, the pencil is for highlighting PDFs containing real text (not an image of text).
I thought it was for drawing on it.

Maybe, an app like scribble could load an image/pdf as background…