The purpose of the calendar in CRM is to monitor activities and services reserved for customers. The Calendar tab cab be used to create/view activities such as calls, meetings, and tasks. "Day-view" is that view of CRM calendar in which activities and tasks can be viewed based on a specific day. You can use the day-view to view a more complete list of tasks and calendar events by following these easy steps:
Step 1: Select 'Calendar' tab

On ribbon, click the "Calendar" tab.
Step 2: View the Day Details

At the top of screen, in right hand side pane, three tabs are available: Day, Week and Month. Select the "Day" tab.
Right below "Day" tab, a day view is presented against each hour of that day. Here you can view details about your daily tasks. To edit any task, double-click on it, make changes that you want to have in it, click 'Save & Close' when you have done.
This view is similar to Microsoft Outlook calendar's view.