How To Set a Default Currency
To set a default currency, hover over the "User" tab on the top menu and click on "My Profile" from the drop-down options.
Click on "Update Company Information".

Click on "Default Currency" at the bottom of the form and select your preferred currency from the drop-down menu.
Click the green, "Save Changes" button.

Tip:You can select specific currencies for properties when you link them to a bank account.
View Steps to Simple Accounting for more information on bank accounts.