component.js

<form>
  <lightning:input label="Name"
                   type="text"
                   required="true"
                   aura:id="field"
                   name="Name" />

  <lightning:input label="Email"
                   type="text"
                   required="true"
                   aura:id="field"
                   name="Email" />
                     
  <lightning:button aura:id="submit-button" label="SUBMIT" type="submit" onclick="{!c.submitForm}" />
    
  <aura:if isTrue="{!v.formMessage}">
      <ui:message severity="error" closable="false">
          {!v.formMessage}
      </ui:message>
  </aura:if>

  <iframe aura:id="vfFrame"
          class="slds-m-top--medium"
          src="/apex/VFrecaptchaPage"
          scrolling="no" frameborder="0" height="500px" width="350px" allowtransparency="true">
  </iframe>
</form>