A test PayPal account allows you to test transactions without using real money.
To create a test PayPal account, follow these steps:
Log in to https://developer.paypal.com with your PayPal account details.
Create a pre-configured account.
Select the options you want and select Create Account.
In case of PayPal Standard, click Test Accounts, copy the test email address and set this as your Paypal email in JRNI.
In case of PayPal Pro, log in into recently created account in order to generate API credentials which you can then enter in JRNI.
With the test account setup in PayPal and JRNI, you can now make test bookings and payments. When you're ready to take real payments, make sure you update your PayPal details in JRNI.