# How to add GSTIN to E-Invoicing?
1\. Log in to your ClearTax E-Invoicing sandbox account - or your ClearTax E-Invoicing production account - based on which environment auth token you want to generate.
2\. On the bottom left corner click on “Settings”.
3\. On the sidebar menu, click on “Business Settings” and then click on the “Add New Business” button. You will see a modal window like below.
4\. In the “GSTIN” field, type “29AAFCD5862R000”. In the “Display Name” field, type
“Sandbox Karnataka”. In the “NIC API Username” field, type “cleartax”. In the “NIC
API Password” field, type “Defmacro\@123”. And then click on the “Add Business”
button.
5\. Repeat steps 3 and 4 above for all the sandbox GSTINs as per your usage.
NIC API Credentials - [The list
of available Sandbox GSTIN, NIC username and password is available on this page. ](https://docs.cleartax.in/cleartax-docs/e-invoicing-gsp-api/getting-started-with-einv-gsp-api/sandbox-gstin-for-einv-gsp)
Clear IRP API Credentials - [The list of available Sandbox GSTIN, Clear IRP Username and Password is available on this page. ](https://docs.cleartax.in/cleartax-docs/e-invoicing-api/learn-e-invoicing-api-basics/how-to-add-gstin-to-e-invoicing/clear-irp-api-credentials)
