You can have the PayPal button showing up after submission of a form.
- Copy the PayPal button code from PayPal, then in the Admin section click “Contact” for Contact 7 forms.
- Select your form, then scroll to “Messages”
- Paste your code into the part this part:
# Sender's message was sent successfully"
So after user submits form successfully they can click on the PayPal button to pay.