Welcome to the Community. It's essential to correctly record your transactions in order to keep your books balance. QuickBooks Online is a great program that offers the ability to simply track your sales and expenses. I'd glad to point you in the right direction to make an expense record for 100 percent tax.
I'd encourage you to refer to the following steps to record the expense.
The expense of 100 percent tax will be recorded in your books.
Let me know if you have any questions, I'll be happy to help.