A billing administrator can email an invoice with a PayPal link so that clients can pay directly through PayPal.
1. Go to 'Settings' > 'System Settings' > 'Accounting' and fill in your PayPal account details
2. Go to 'Accounting' > 'Global Settings' > 'Funders' and check off the box 'Allow PayPal payment'
3. From the list of invoices, click on 'Email' from the 'View' dropdown
4. On the 'Email Invoice' popup, make sure that 'Include PayPal link' is checked off and click 'Send.'