Where do I enter the GST information of my customers/vendors?

You can enter the GST information of your customers/vendors in the their respective contacts in Contacts module. To enter the GST information:

• Go to the Contacts module in Zoho Books.
• Select the respective customers/vendors’ contact.
• Click Edit from the top bar.
• Select the appropriate GST Treatment. 
• If you’ve selected Registered Business:
  • Enter the GSTIN of the contact. 
• Select the appropriate Place Of Supply. 
• Click Save.