By default, Directory Opus will display Today, Yesterday, or the name of a day (Monday, Tuesday, etc.) for dates within the last week:
(Short-distance time travellers may even see Tomorrow for dates in the future.)
If you don't like this, turn off Preferences / Folders / Folder Display: Show day names in date columns if date is within one week:
Another option on the same page lets you turn seconds and milliseconds on and off in time columns:
Beyond those options, the way Opus displays dates and times is usually defined by your system locale.
In Windows 10, the 'Metro' settings dialog is as half-finished as usual and only allows you to select from a few preset formats:
But if you open the old Control Panel, then select Change date, time or number formats, then choose Additional Settings..., you can type in any date format you wish (within reason):
A lot of software caches the formats on startup, so you may need to reboot for everything to update.
(Note that some poorly written/tested software will assume the date format is always the US-style MM/dd/yyyy and can break if you use other formats. It is rare, but is worth being aware of in case something starts to misbehave.)
If you are using Opus Pro, you can also override the system-wide date and time formats, should you for some reason wish to show dates and times differently in Opus compared to everything else on your system: