Unable to add "radio buttons", "checkboxes" and "selects" to Contact Form on Web Presence Builder.
Web Presence Builder 11.5 supports only additional fields in the Contact Form. For more details refer to Web Presence Builder User's Guide (Page 31)
"radio buttons", "checkboxes" and "selects" in Contact Form are not supported in Web Presence Builder at the moment. You may want to suggest new functionality in Plesk on Plesk User Voice portal.
The top-ranked suggestions are likely to be included in the next versions of Plesk. You can get the information about the updates in our products in the following public sources: