Hi kaweka
In Essentials Accounting you can change the GST settings per this Help article: GST Settings. After changing the settings, you do need to manually change the tax codes for your accounts.
This help article Changing your GST settings explains the tasks to do after changing GST settings in the new Essentials/MYOB Business, while both products have their differences, I'd suggest checking it out as it would still provide you with more details on the tasks to do and to check after changing the settings.
If you have any further questions please feel free to reach out.