PayPal Standard User Payment Process
When user fills out any of the integrated online forms on your Wild Apricot website (e.g. membership application or event registration) and choses to pay online, they will be redirected to PayPal page where they will have an option to pay either with credit card or with PayPal account. User does not have to have or open a new PayPal account in order to complete the transaction, but they will see an option to create it on the payment page.

After the payment is submited, PayPal will validate the transaction and show a payment confirmation page.
The confirmation page will show a summary of the transaction and provide a link that will take the user back to your Wild Apricot website. Note that at this point the user can chose (or not to) to click on this link and there is no guarantee that they will return to your website after making a payment.