Utility for sending single emails in Apex with an org-wide email address

EmailSend.cls

public class EmailSend {

    public static void sendEmail(String candidate){
        Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();
        mail.setToAddresses(new String[]{candidate});
        mail.setReplyTo('hr_address@my_company.com');
        mail.setSubject('Thank You');

        // https://help.salesforce.com/articleView?id=000340122&type=1&mode=1
        // org-wide email address needs to be set
        OrgWideEmailAddress[] owea = [select Id from OrgWideEmailAddress where Address = 'hr_address@my_company.com'];
        if ( owea.size() > 0 ) {
            mail.setOrgWideEmailAddressId(owea.get(0).Id);
        }

        mail.setHtmlBody('<p>Your message has been recieved</p>');

        mail.setPlainTextBody('Your message has been recieved');

        Messaging.sendEmail(new Messaging.SingleEmailMessage[]{mail});
    }

}