The TODAY function returns today's date (or the date the report is Output), specifically at 12:00:00 AM.
If you want the value to Print, use an Out Tag. If you just want to reference the date, and not print it, use a Set Tag.
Use this to run reports by setting start and end dates based off of today. If you need to set a date for the previous month, use =TODAY() - DATESPAN(0,1,0).
If you are using XML or JSON with an Out Tag, you want to make sure that the date in your data source is formatted to match those standards, which are an American format.
You can use the Tag's formatting interface to choose the style for your output.