You'll need to create an API username for PayPal. You can access PayPal via API only if you have a PayPal Premier / Business / Website Payments Pro account.
Follow these steps:
1 . Log into your PayPal account.
2. Click the Settings icon.
3. Click the Profile tab. If you haven't already done so, you need to verify your account before requesting API credentials. Next click on 'My Selling Tools'.
4. Click into the API Access settings
5. Click into 'Manage API Credentials'
6. On the next page that opens, click on the Show link and copy the values into KennelBooker on the following page.