The app doesn't support this feature

Why can't the app allow me to draw arrows? It's hard to communicate using the chat and often my partner doesn't look at the chat or use it. So how am i supposed to communicate?

You can't. Is the simple answer

You can’t sorry

I don’t play any type of chess game except slow chess on the app

I was hoping I could double tap and drag to draw arrows but it doesn't work.

I can't suggest an alternative "right click for apps". I guess most of you play on the computer. So much for drawing arrows.  

if it is an android then buy OTG and connect mouse to the OTG but i don't know if it will work.