Fix PHP form for my website

I need to have a PHP form on my website fixed. I do not think it's very difficult, but I am very inexperienced with PHP. The user goes to my page and checks a few radio buttons. He fills out form fields with his title (Mr./Mrs./etc.), his first name, his last name, and an email address. Depending on which buttons he checks, a different number is generated. An email should be sent to him and to the website administrator with that number and a custom message. I will share the URL of the page with the form with serious bidders.