Captcha for joomla core and custom forms.Inserts captcha in registration,contact,reset password, remind username forms on enabling this plugin.To add captcha in custom forms without changing any existing codes or admin settings, follow the steps mentioned below.
Just have to follow 3 steps for core forms.
1.install the plugin
2.publish the plugin
3.choose JRCaptcha on global configuration
Integration with All Joomla Forms