Panels + Recaptcha : how to add a (re)Captcha in my panels view? I've just installed Panels 3.1 on my D7 website.

There is no options to add a Recaptcha form on my Panels view.

Where should I find that ?

Thank you,
You don't usually add a recaptcha directly to Panels; you'll want to add it to the appropriate form(s) (comment, registration, etc.)  When you do so, adding the appropriate form in Panels should automatically pull in the recaptcha as well.