This depends on what you are using easiForm with, select from the following links for the easiForm that suites your needs:
If you want to use easiForm in Freeway 4 Pro or above then select this PHP easiForm tutorial, this is an action suite that can be used with Freeway and avoids hand coding as it is just a matter of adding the actions to your form.
PHP easiForm - easiForm actions suite for use with Freeway 4 + Pro
The following link is to the tutorial page for adding easiForm scripts to your web form.
easiForm scripts - For those that prefer to hand code the easiForm scripts in forms.
easiForm can be further extended using the easiCaptcha, for more information on easiCaptcha see here.