You can use Notepad to create a log file that adds the current date and time each time the file is opened. This is the way you can do it.
Start Notepad. It opens a blank text file, just type .LOG on the first line and click enter.
Save the file using Save or Save as option and close the file.
Reopen the file and you can see date and time have been appended to the end of the log as shown below.
Each time you reopen file a log entry is created with date and time.
This trick is very helpful to create log of daily tasks.
This is a small trick I got it from the Microsoft support site.