A sample lightning form along with Quick Action

quictActionForm.cmp

<aura:component implements="force:lightningQuickAction,force:hasRecordId" controller="SourceSendEmailController">
    <aura:attribute name="subject" type="String" />
    <aura:attribute name="emailId" type="String" />
    <aura:attribute name="body" type="String" />
    
    
    <lightning:input aura:id="emailform" name="input2" label="Email Id"  value = "{!v.emailId }" required="true"/>
    <lightning:input aura:id="emailform" name="input1" label="Subject" value = "{!v.subject }" required="true"/>
    <lightning:textarea aura:id="emailform" name="input3" label="Body" value = "{!v.body }" required="true"/>
    <br/>
   
    <div class="slds-align_absolute-center">
    	<lightning:button variant="brand" label="Send Email" title="Send Email" onclick="{! c.validate }" />
    </div>
    
</aura:component>

quictActionFormController.js

validate: function(component, event, helper) {
        var isValid = component.find('emailform').reduce(function (validSoFar, inputCmp) {
            // Displays error messages for invalid fields
            inputCmp.showHelpMessageIfInvalid();
            return validSoFar && inputCmp.get('v.validity').valid;
        }, true);
        // If we pass error checking, do some real work
        console.log('isValid********' + isValid);
        if(isValid){
            helper.sendEmailJS(component, event, helper);
        }
    }