@Bee-liever Okay but I want it to be yyyy.mm, which is not the same format as my Windows.
Go to Preferences > Tags (1) > Under "custom tags", click Define New Tags... > Under one of the things called "label" name it Date, then under "formula" put
$Date(<Year>,yyyy-MM-dd) and save it.
Then enable Date as a display field instead of Year. Windows does mm/dd/yyyy by default, and this will force everything to yyyy-mm-dd for the "date" as long as everything is properly filled out. All you have to do is enter this in the Year tag in the metadata.