Hi,
Not sure if you are asking about something localization related, but if your question is only about date time formatting the following might be the answer:
Go to Language in the menu → Language settings → Open your (default) language under the tab languages → Here you can change the way dates and times are formatted for display by default in your application.
Take a look at this learning path to understand more of the DateTime handling and localization in Mendix:
https://academy.mendix.com/link/module/374/lecture/3046/7.1-Introduction