Sending Email Automatically when due date

Dear Expert,

I understand by using Macro, it able to send email out on certain date.
I attached a worksheet here, I would like the excel to send out email to certain group of people depends on the PIC on
21 days before column J, to inform them to renew the documents.

If macro can do this, it will really help me alot on time consuming.

Thanks in advance for your help.

Regards,
CY