Hi Yash,
I can use the below code for sending the email. I also used it in my org.

trigger SendEmailOnCase on Case (after insert, after update) {
    Set<Id> conIds = new Set<Id>();
    List<Messaging.SingleEmailMessage> mails = new List<Messaging.SingleEmailMessage>();
    for (Case c: trigger.new) {
        conIds.add(c.ContactId);
    }
    Map<Id, Contact> conMap = new Map<Id, Contact>([SELECT Id, Email FROM Contact WHERE Id In :conIds]);
    
    for (Case c : trigger.new) {
        if (c.status == 'Closed') {
            Contact relatedCaseContact = conMap.get(c.ContactId);
            
            Messaging.SingleEmailMessage CaseNotificationmail = new Messaging.SingleEmailMessage();  
            CaseNotificationmail.setToAddresses(new List<String> { relatedCaseContact.Email });
            CaseNotificationmail.setReplyTo('khananasrehmani@gmail.com');
            CaseNotificationmail.setSenderDisplayName('Salesforce');            
            
            CaseNotificationmail.setSubject(' Case Status updation : ' + 'Changed to ' + c.status + '. Case Number:' + c.CaseNumber);
            CaseNotificationmail.setPlainTextBody('Your case Status for Case Number: ' + c.CaseNumber + ' has been closed'); 
            mails.add(CaseNotificationmail); 
        }
    }
    Messaging.sendEmail(mails);
}

I hope you find the above solution helpful. If it does, please mark it as Best Answer to help others too.
Thanks and Regards,
Sachin Arora
www.sachinsf.com