LibreOffice can automatically format dates that you have entered into a table, according to the regional settings specified in your operating system.
Do one of the following:
When this feature is on, a check mark is displayed in front of thecommand.
Choose LibreOffice - PreferencesTools - Options - , and select or clear the check box.
This feature applies globally to all tables in all documents. When enabled, typing a date into a table cell will result in automatic formatting. Enabling and disabling this feature does not change existing data formatting.