You will be asked to confirm your handicap after every round in the signing off process. If you change it here and sign the round off your handicap will automatically be updated.
You can also manually change your handicap in the settings of your mobile app or the online dashboard website.
*Click the settings menu top right of the screen
*From the drop down options select the 'Account' option
*Click on the 'Handicap' option and select your new handicap
*Press the 'Save all Details' button bottom right