This variable sets the date format. This format applies to all timestamps or date fields. When loading data, Qlik Sense will automatically tag date and timestamp columns with the $timestamp and $date tags, which are the ones that will inherit this formatting.

While in Europe, we would set this variable as follows:

SET DateFormat = 'DD-MM-YYYY';

In the United States, we would have to set the variable as follows:

SET DateFormat = 'MM-DD-YYYY';

My favorite, however, is the ISO date format, which makes it the clearest version of them all:

SET DateFormat = 'YYYY-MM-DD';