The Chat Area itself cannot be made bigger, however you can change the text size in the club's SET-UP.
Click SETUP after entering the bridge club --> Text Size Options and choose one of the options.
If you're happy with your changes, you have to update your desk top App:
Leave the club - (close the app and related windows completely)
Go to the BridgeClubLive or Bridge4Free home page (whichever is applicable) and click [Click here to play] or [Install & Play]. The changed Settings are now remembered for the next time.
Examples are shown below
normal size :
Normal Size converted into CAPITALS:
LARGE converted into Capitals: