Hi,

Thanks for the reply the below code tested using execute anonymous window code it is sending emails.

But how to schedule this and make it work as per actual requirement. Starting from 3rd day of month from there onwards every 3 days i want to schedule.

Plz help me with this.

Batch Class:-

public class AttendanceAuto implements Database.Batchable<SObject>, Database.AllowsCallouts, Schedulable {
    
     public void execute(SchedulableContext sc) {
        Datetime now = Datetime.now();
        Integer dayOfMonth = now.day();
        
        Datetime startDate = Datetime.newInstance(now.year(), now.month(), 3, 0, 0, 0);
        if (dayOfMonth > 3) {
            startDate = startDate.addDays(dayOfMonth - 3);
        }
        
        Datetime nextRunTime = startDate;
        while (nextRunTime <= now) {
          //  System.schedule('Attendance Batch Job', nextRunTime, this);
            
            nextRunTime = nextRunTime.addDays(3);
        }
    }

    public Database.QueryLocator start(Database.BatchableContext context) {
        Datetime batchStartDate = System.now().addDays(-3); 
        Datetime batchEndDate = System.now();
        
        return Database.getQueryLocator([
            SELECT Id, Name, Employee__c, Employee__r.Name, Employee__r.Email__c, Employee__r.Manager__r.Email__c, Statuss__c, Date__c, CreatedDate, Processed__c
            FROM Attendance__c 
            WHERE (Statuss__c = 'Shortfall' OR Statuss__c = 'Present' OR Statuss__c = 'Less than 9.15' OR Statuss__c = 'Status Unknown')
            AND CreatedDate >= :batchStartDate AND CreatedDate < :batchEndDate
            AND Processed__c = false
        ]);
    }
 public void execute(Database.BatchableContext context, List<Attendance__c> scope) {
        List<Messaging.SingleEmailMessage> emailsToSend = new List<Messaging.SingleEmailMessage>();

        for (Attendance__c att : scope) {
            try {
                if (att.Employee__r != null && att.Employee__r.Name != null && att.Employee__r.Email__c != null && att.Employee__r.Manager__r != null && att.Employee__r.Manager__r.Email__c != null) {
                    Messaging.SingleEmailMessage email = new Messaging.SingleEmailMessage();
                    email.setToAddresses(new List<String>{att.Employee__r.Email__c});
                    email.setCcAddresses(new List<String>{att.Employee__r.Manager__r.Email__c});
                    email.setSubject('Attendance Status Notification');
                    
                    Datetime dateAndTime = DateTime.newInstance(att.Date__c.year(), att.Date__c.month(), att.Date__c.day());
                   // String formattedDateAndTime = dateAndTime.format('MMMM dd, yyyy h:mm a', 'UTC');
                   // + formattedDateAndTime
                    email.setPlainTextBody('Dear ' + att.Employee__r.Name + ',\n\n' +
                       'Your attendance on Submitted Date:- '+ att.Date__c +', Created Date:-' + att.createdDate +' has a status of "' + att.Statuss__c + '".\n\n' +
                       'Please review your attendance record.\n\n' +
                       'Record Link: https://-dev-ed.develop.lightning.force.com/lightning/r/Attendance__c/' + att.Id + '/view' +
                       '\n\nSincerely,\nSalesforce');

                    emailsToSend.add(email);
                    att.Processed__c = true;
                } else {
                    System.debug('Skipping record with Id: ' + att.Id + ' due to missing or invalid email addresses.');
                }
            } catch (Exception ex) {
                System.debug('Error processing record with Id: ' + att.Id + '. Error: ' + ex.getMessage());
            }
        }
        
        update scope;
        
        if (!emailsToSend.isEmpty()) {
            Messaging.SendEmailResult[] results = Messaging.sendEmail(emailsToSend);
            for (Messaging.SendEmailResult result : results) {
                if (result.isSuccess()) {
                    System.debug('Email sent successfully.');
                } else {
                    System.debug('Failed to send email. Error: ' + result.getErrors()[0].getMessage());
                }
            }
        } else {
            System.debug('No emails to send.');
        }
    }

    public void finish(Database.BatchableContext context) {
    }
}