A reminder is a message that informs people of upcoming events. In SharePoint, we also need reminders to notify users of upcoming changes. These changes are always related to a list or a document library. To receive notifications about them, use the Virto Alerts & Reminder App to create an automatic email reminder.
Example
You have a SharePoint list of team members with their personal information, which is the same list we used as an example for alerts. Tom Foster is responsible for preparing corporate presents for people’s birthdays. You would like Tom to be informed about each upcoming birthday one week before the date, so you use the Virto Alerts & Reminder App to create an automatic reminder.
To summarize, a reminder is an email notification about upcoming changes in a SharePoint list or document library.