Hello Everyone, In this tutorial, I am going to show an example that helps you to send calendar invites using apex class. You can use this example according to your need to send invites for meetings or for any business purpose. This sample code shows you how to do that, So let's get started,

 Send Calendar Invites using Apex

 Step 1: Login to your Salesforce Org. and open developer console.

Step 2: Navigate to File | New | Apex Class and Create an Apex controller called CalendarInvites using the following syntax.

 CalendarInvites.apxc 
 public class CalendarInvites {
    
    public static void sendinvite() {        
        Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage(); 
        mail.setToAddresses(new List<String>{'smanisheng@gmail.com'});
        mail.setSubject('Meeting Invitation');      
        mail.setPlainTextBody('');     
        Messaging.EmailFileAttachment attach = new Messaging.EmailFileAttachment();   
        attach.filename = 'reminder.ics'; 
        attach.ContentType = 'text/calendar';     
        attach.inline = true;     
        attach.body = invite();   
        mail.setFileAttachments(new Messaging.EmailFileAttachment[] {attach});   
        Messaging.SendEmailResult[] er = Messaging.sendEmail(new Messaging.Email[] { mail }); 
    }
    
    private static Blob invite() {
        DateTime dt=DateTime.now().adddays(1);
        String startdatetime=String.valueof(dt.year()+'0'+dt.month()+''+dt.day()+'T000000Z');
        String enddatetime=String.valueof(dt.year()+'0'+dt.month()+''+dt.day()+'T020000Z');
        String txtInvite = ''; 
        txtInvite += 'BEGIN:VCALENDAR\n';        
        txtInvite += 'PRODID::-//hacksw/handcal//NONSGML v1.0//EN\n';
        txtInvite += 'VERSION:2.0\n';
        txtInvite += 'METHOD:PUBLISH\n';
        txtInvite += 'X-MS-OLK-FORCEINSPECTOROPEN:TRUE\n';
        txtInvite += 'BEGIN:VEVENT\n';
        txtInvite += 'CLASS:PUBLIC\n';
        txtInvite += 'CREATED:20091026T203709Z\n';        
        txtInvite += 'DTEND:'+enddatetime+'\n';
        txtInvite += 'DTSTAMP:20191026T203709Z\n';        
        txtInvite += 'DTSTART:'+startdatetime+'\n';
        txtInvite += 'LAST-MODIFIED:20091026T203709Z\n';
        txtInvite += 'LOCATION:India\n';
        txtInvite += 'PRIORITY:5\n';
        txtInvite += 'SEQUENCE:0\n';
        txtInvite += 'SUMMARY;';
        txtInvite += 'LANGUAGE=en-us:Meeting\n';
        txtInvite += 'TRANSP:OPAQUE\n';
        txtInvite += 'X-ALT-DESC;FMTTYPE=text/html:<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"><HTML><HEAD><META NAME="Generator" CONTENT="MS Exchange Server version 08.00.0681.000"><TITLE></TITLE></HEAD><BODY><!-- Converted from text/plain format --></BODY></HTML>\n';
        txtInvite += 'X-MICROSOFT-CDO-BUSYSTATUS:BUSY\n';
        txtInvite += 'X-MICROSOFT-CDO-IMPORTANCE:1\n';
        txtInvite += 'END:VEVENT\n';
        txtInvite += 'END:VCALENDAR'; 
        return Blob.valueOf(txtInvite);
    }
 }
Step 3: In developer console, Navigate to Debug | Open Execute Anonymous Window or press CTRL+E and execute the following line of code to see the output (don't forget to replace setToAddresses with your email in above code example),
 CalendarInvites.sendinvite();
Output:

See also:

Conclusion:
Hope you like this tutorial, for any query or suggestions please feel free to comment.
Thank you.