Adding time.

How do you add time for your opponent ? Also unable to use chat room while playing apart from GG/WP etc. Using mobile. Tia.

Normally there is a blue plus icon to the right of your opponent's time. However, both the "add time" button and the chat option can be hidden.

Thanks so how do I un hide it ?

You opponent can turn off both of these features.
You can turn off the "add time" by clicking your username in the top right corner, "preferences", "chess clock", and choose from the last option.
During a game, there's a button in the upper right corner of the chat box which toggles the use of the chat box. Both players must enable the chat box for the chat box to be in use.

Got it thanks very much will experiment when next playing.

I do not see the reasons of adding time beside trolling

#6 Sometimes my opponent disconnect (lag?) for some times and 'll probably just lose on that.
Or easier, let's say I play against a friend and I'm more interested in getting the game to the end than scoring 1 point.

On mobile you can only add time in landscape mode.. afaik. It seems to be a bug. So you have to unlock your screen rotation and then turn your phone...