You will need to know GSTIN of your suppliers in GST tax regime, to generate GST compliant invoices and returns, and avail your input tax credit. Here’s how you can add the GSTIN for your suppliers:
 

 Add a supplier for the first time in QuickBooks:

  1.  Click Expenses from the left menu
  2. Click Suppliers and click Add a supplier
  3. Enter supplier’s information along with his GSTIN in Supplier Information
  4. Click Save
  5. Your first supplier and his GSTIN are saved
     

 Add GSTIN of new supplier:

  1.  Click Expenses from the left menu.
  2. Click Suppliers
  3. Click New supplier on the top right
  4. Enter supplier’s information along with his GSTIN in Supplier Information
  5. Click Save
  6. Your new supplier’s GSTIN is saved.
 

Add GSTIN of existing supplier:

  1.  Click Expenses from the left menu
  2. Click Suppliers
  3. Click on the supplier’s name for whom you want to enter GSTIN
  4. Click Edit on the  top right.
  5. Go to GSTIN in Supplier’s Information
  6. Enter your supplier’s GSTIN and click Save