For each contact there is a section called Tasks. Here you can add todos and/or calendar entries.
Each task allows you to select who the assignee will be. This dropdown includes all users associated with your website.
The todo type allows you to set up todos with or without due dates. These will appear in the assignee's todo list.
For each todo, you can add a description, optionally notify the assignee of the task, add a due date, and if a due date is set, add a reminder. The due date setting allows you to select the date and time (in 15 minute intervals) or Anytime. The anytime option is selected by default. Reminders allow you to set a time period (X number of minutes, hours, days, or weeks) prior to the due date where the assignee will be notified that they still have an outstanding todo. Multiple reminders can be added.
Type: Calendar Entry
Calendar Entries allow you to add entries to a calendar on specific dates and times. This option also has a repeat setting, allowing you to repeat the entry daily, weekly, monthly, or yearly. Repeating events can additionally have no ending date, an ending after X number of times, or a specific end date.
Reminders for calendar entries can also be set like todo reminders, X number of minutes, hours, days, or months before the event.
See All Tasks Assigned to a User
While you can see all the tasks for a contact on their contact page, you can also see all the tasks assigned to any user by visiting Contacts & Forms > Contact Tasks. Here you can select a specific user and see all the calendar entries and todos currently assigned to them, separated by contact. Additionally, you can see any past due items that may have been missed.