Hi Ranjith,
Try the below code to send an email to logged in user
Create below components :
1. SendEmail.cmp  -- Lightning componnet
2. EmailSendController  -- apex controller

SendEmail.cmp 
   
<aura:component controller="EmailSendController">
    <aura:attribute name="mailId" type="String"/>
   <aura:attribute name="mailStatus" type="boolean" default="false"/>
   <aura:if isTrue="{!v.mailStatus}">
      <div role="alertdialog" tabindex="-1" aria-labelledby="prompt-heading-id" aria-describedby="prompt-message-wrapper" class="slds-modal slds-fade-in-open slds-modal--prompt">
         <div class="slds-modal__container">
            <div class="slds-modal__header slds-theme--error slds-theme--alert-texture">
               <h2 class="slds-text-heading--medium" id="prompt-heading-id">Mail Status</h2>
            </div>
            <div class="slds-modal__content slds-p-around--medium">
               <div>
                  <p>Email Sent successfully to {!v.mailId}</p>
               </div>
            </div>
         </div>
      </div>
      <div class="slds-backdrop slds-backdrop--open"></div>
   </aura:if>
   <div class="slds-m-around--medium">
      <div class="slds-container--medium">
          <lightning:button label="sendEmail" onclick="{! c.sendMail}"/>
      </div>
   </div>
</aura:component>

SendEmailController.js

({
    sendMail: function(component, event, helper) {
            helper.sendHelper(component);
    },
})

SendEmailHelper.js

({
    sendHelper: function(component) {
        var action = component.get("c.sendMailMethod");    
        action.setCallback(this, function(response) {
            var state = response.getState();
            alert('state&& '+state);
            if (state === "SUCCESS") {
                var storeResponse = response.getReturnValue();
                alert('res '+storeResponse);
                component.set("v.mailStatus", true);
               // component.set("v.mail", UserInfo.getUserEmail());
            }
 
        });
        $A.enqueueAction(action);
    },
})


EmailSendController -- apex controller

public class EmailSendController {
 @AuraEnabled 
    public static void sendMailMethod( ){
    String mMail ;
        String mSubject = 'test mail from lightning';
        String mbody = 'Hi' +UserInfo.getFirstName();
        mMail = UserInfo.getUserEmail();
        System.debug('user mail id '+mMail);
     List<Messaging.SingleEmailMessage> mails =  new List<Messaging.SingleEmailMessage>();     
  
     // Step 1: Create a new Email
       Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();
    
    // Step 2: Set list of people who should get the email
       List<String> sendTo = new List<String>();
       sendTo.add(mMail);
       mail.setToAddresses(sendTo);
    
    // Step 3: Set who the email is sent from
       mail.setReplyTo('noreply@gmail.com'); // change it with your mail address.
       mail.setSenderDisplayName('salesforce User'); 
    
    // Step 4. Set email contents - you can use variables!
      mail.setSubject(mSubject);
      mail.setHtmlBody(mbody);
    
    // Step 5. Add your email to the master list
      mails.add(mail);
    
  // Step 6: Send all emails in the master list
     Messaging.sendEmail(mails);
   }   
}

Here i have used dummy data for subject and email body. Update the code as per your requirment and test it.
Let me know if you have any...

Thanks