On the mobil devices you may activate a PayPal button on the PDF for orders and invoices. You should set it up at Main Menu> Settings > PDF Documents > Email > Send a PayPal button
Main Menu > Settings
PDF Documents
Email > Send a PayPal button > Enter your PayPal email account
Touch SelBuk Logo > Database
Touch Sales / Invoices
Touch All Orders
On the order Touch the send icon > Email with PayPal button
Select ther currency
The email with PayPal button ready to send