To set your primary company currency, first make sure that you have an Address set up in the Company Settings. Then you can go to Settings > Company > Currency/Tax and select a currency from the dropdown menu.
If you use separate purchasing and selling currencies, or you use different currencies in different projects, click here for more information about our multi-currency tools.
If you have more than one Office set up in Jetbuilt, you may want to change your Office Currencies.