Hi,

The default date format is MM/DD/YYYY. Suppose you need to change the date format to DD/MM/YYYY. To do the same, perform the following steps.

1. Navigate to the “Settings>Translations>Languages” Menu from the Administrator account.
2. Choose the language for which you want to change the date format from the list and open its form view and click on edit to modify.
3. For the format, MM/DD/YYYY, the entry in date format is “%m%d%y”. To change this to DD/MM/YYYY, we can modify it to “%d%m%y” and click on save.

OR

You can use this code.
1 . For forms or tree view use the widget ''date"

2 . For reports or qweb use

for t-esc ->  

for t-fields ->

Hope it helps