You are able to create a Reminder for a specific contact or an internal reminder that can be sent as an Email, SMS, Letter or to create an internal Task.
This can be done in your Web Portal, go to CRM > All Contacts > Select the ID or Arrow for the contact > select the New button in the activity section > select Reminder from the dropdown > Select the Reminder Type and add in the information > Save.
We have created some Suggested Templates for Email, SMS & Task Communication for you to be able to use when creating any type of Communication.