1. You can add Paypal details from below steps:
Moon invoice Pro -> Company -> Edit -> Paypal Email, Here you can add paypal details.
Please make sure that you have enable paypal option from Invoice.

2. You can adjust Paypal details in PDF from below steps:
Moon invoice Pro -> Settings -> PDF settings -> Here you can manage Pay pal details on PDF.

3. You can add Paypal details in Email from below steps:
Moon invoice Pro -> Company -> Edit -> Email Template -> Invoice -> Add Paypal tag to email body Email, You can see paypal link in email.

- Moon Invoice