New Hire email notifcation and reminders (IN LDG)

Summary:

My Client wants to send an email notifcation and reminders to users upon their New Hire Enrollment is processed by HRIS.

Content (required):

I need to create custom email notificaiton when an employee is onboarded as NewHire.

Version (include the version you are using, if applicable):

I am Release ver 13.

Code Snippet (add any code snippets that support your topic, if applicable):

currently, I am trying custom Alerts Composer but it is not working . Also, i wanted to know if anyone has used any custom attributes to meet this requirements.