As some expense types may be subjected to tax, you can create these tax items in the Expense Settings.
Go to Expense > Expense Settings > Tax.
Click on the Add New Tax button to create a new tax item or click the Red Trash icon to delete any of the tax items.
You can choose between:
Automatic: the tax amount will be automatically calculated based on the % value you have set, e.g. GST at 7%
Manual Input: the tax amount will need to be manually keyed in