To get time to register it, use Now function, which returns a date AND time.

In Excel, a date is integer (the number of days at 01.01.1900 00:00:00), and time is decimal part of day. I.e. 1 hour equals 1/24, 1 minute equals 1/(24*60) etc. P.e. I read current time in excel, using NOW() worksheet function, and in General format it was 42998.5644840278