[SOLVED] How to add Validated End Date and Requested End Date in Mail be issued

I am trying to find a way to have the Validated End Date and Requested End date show up in Mail that we receive under Title Description.

I can't seem to find a way to have these two dates displayed in the Emails we receive. At the moment the email we receive with the status of an activity is changed is only Creation date.

I would also like the Validated End Date and Requested End Date to show.

Can someone tell me how to do it. I know this would require coding in the php files. This is not an issue, but with so many files, I need to know where the exact file is to make the change and also the name of the variable (field) to identify it, so it is displayed in the emails.

I thought I can do it with my basic understanding of php.

Having gone through the coding in the file, I realised, that this is not something I can do without assistance.

Would you be so kind as to provide me with coding to add these two dates in the emails that are sent, including where I should enter the data?