We suggest you to please add the solar product with 12% and add the product as a service with 18% tax rate. Please follow the below mentioned process.
Kindly go to the products and services>>Click on add new item>>Solar Product>>Tax rate 12%>>Click on add item.
Click on add new item>>Services>>Tax rate 18%>>Click on add item.
Once the products are added, go to the invoice >> Click on create invoice >> Add the customer >> Add the solar product >> Then Services >> Click on save.
