When you enable date recognition, TextEdit automatically detects dates and times when you move the pointer over them. In addition to standard dates (for example, March 3) and times (for example, 6 P.M.), TextEdit recognizes relative dates (for example, next Friday) and time expressions (for example, tomorrow).
TextEdit outlines date and time values as a field with a pop-up menu. Click the arrow and choose an option to instantly create a new iCal event or show the event for a particular date.
To enable date recognition in the current document, choose Edit > Substitutions and then select Data Detectors in the submenu.
To enable date recognition in all new documents, choose TextEdit > Preferences, click New Document, and then select “Data detectors” below Options.