QuickBooks Online has a default tax for Cess. These are Swachh Barat Cess and Krishi Kalyan Cess. To show this on the tax rate list, you'll need to add them from the Taxes page.
Click Taxes at the left panel.
Choose the Add tax button and select Tax rate.
Enter the tax name and description.
Click the Tax Agency drop-down and choose one of the cess on the list.
Checkmark the Purchase box. Then, enter the rate.
Choose an account.
Once done, you can now go to the Purchase Bill page. Then, fill in the necessary fields including the option to choose the Cess you've created under the Tax column.
If the cess is not under the default stated above, I'd recommend creating a custom tax. While doing this, I'd suggest consulting an accountant for further guidance on setting it up. This is to ensure your books are accurate in QuickBooks Online (QBO). Please follow the steps below.
Go to Taxes from the left menu.
Click the Add Tax button.
Select Custom tax.
Enter the Tax Name, Tax Agency Name, and other necessary information.
Checkmark the This is Kerala Flood Cess and This tax is collected on purchases boxes.