date format

[Dolly123]

Change Date Format from MMM-YY to DD/MM/YYYY in Qlik Sense

[Gabbar]

In your date Format there is no mention of Day number.
So to generate 1st date of respective month use:
MonthStart(Date(Date#(DateField,'MMM-YY'),'DD/MM/YYYY')).
To create last date of month use MonthEnd.

[BrunPierre]

Hi, like this.

Date(Date#('Feb-23', 'MMM-YY'), 'DD/MM/YYYY')

or

Date(Date#(YourField, 'MMM-YY'), 'DD/MM/YYYY')

[Gabbar]

if you just want to change for Feb-23 in UI you can use first one,
If you want to do this to all values in the column use second one.