As a paypal business account holder, what fees do I pay for a transaction with a client in Canada?

Jotform does not charge anything extra when our users use any of our PayPal payment app and integrate it with their PayPal Business account.

https://www.jotform.com/paypal/

https://www.jotform.com/paypal/faq/

You may, however, need to upgrade your account to a paid plan if you are looking to collect payments using your form(s) more than 10 times in a month. You may visit our Pricing page to learn more about the features and limits we have for each plan subscription we have available.

https://www.jotform.com/pricing/

You may also find this guide helpful:

Understanding-Your-Account-Usage-Limits

Feel free to let us know if you need any further assistance.