If you are creating a new organization for your business in Zoho Books, then you can enable GST during the initial quick setup by providing the relevant details. Else, you can enable GST in the Tax Preferences, provided you’re using the Indian edition of Zoho Books. To enable:
Click the Gear icon on the top-right corner and select Taxes.
Select GST Settings.
Check Is your business registered for GST? and enter your GSTIN.
If you’ve registered for the composition scheme, check the Is your business registered for composition scheme? option.