Adding Sales Tax
First, go to the Tenant's tab, and click on the red dollar sign for the tenant you are charging tax to.
If this is to be a recurring charge, be sure to choose that option as you are completing fields:
The result of this recurring charge in the tenant ledger:
Note: If you are charging rent "x" amount of days before the due date (Accounting default settings), and you want both charges to appear in the tenant ledger in advance, be sure that your transaction has a begin date prior to the rent due date as well.