You can quickly insert the current date, time, and your name in any editable text field within an object record or an action form. That stamp has the following format: [Date] [Time] - [User Name]. The date and time format depends on your local settings, the name is the FullName value of your Person record.
For example, the stamp may look as follows:
4/28/2016 2:28:27 PM - Damien Spears
To insert a stamp: