Insert date with long and short options. See Boxer text editor for reference.
However, I would expand on what Boxer implemented to include user customization such as, always use 2 digits for month and day. ie: 1/1/15 becomes 01/01/15. This allows tables to always be aligned. Further, provide the options for 2 digit vs. 4 digit year.
And lastly, but a favorite of mine, provide the option for ISO 8601 date format. See
http://en.wikipedia.org/wiki/ISO_8601 . Allow an option the user to just use the date portion. I normally name files that have date specific as follows: Project_x_requirements_2015_01_01.txt. Also, our version header file in the source code is:
/*
Date Author Comment
2014-09-09 J.Brown Get On Up!
2014-05-12 Johnnie B. Good Rocked it
*/