use the chess board icon in the left corner of the reply box.
suggestions
it is that thing that have little boxes in it. next to it is a green tree and then the big B for bold text.
using the web, never tried to post from the app. there is a row of icons on top of the reply box, include bold, image, font, etc, it is the one on the far left.
Not sure, never tried to do that before, why would you want to do that any way, it is a pain to type on the apps.
how can i share games of chess com in forums