This payment method may not be included in every Funraise plan.
First, be sure that your PayPal account has been connected (instructions here) and confirmed. Once that is done, you can decide on the currency types that you will accept. Certain currencies require a bit of custom coding to display the proper World Currency Symbol (see instructions for doing that here).
To Update your PayPal Account to Accept Multiple Currency Types:
Log in to your PayPal account
From the main menu, click on "Summary"
On the following page, select the currency that you would like to accept and click the button that says "Add Currency"