@hninyuaung
I placed this code inside a gallery, but you can use it in a collection as well if you want?
ForAll(
Sequence(
DateDiff(dpStart.SelectedDate, dpEnd.SelectedDate, TimeUnit.Months) / Value(mthInput.Text)),
{
Date: DateAdd(dpStart.SelectedDate,Value * Value(mthInput.Text), TimeUnit.Months)
}
)
My on screen setup, and resulting output

Note: this code will only work for units in Months. If you need other units, eg Days, Weeks, Years then you will need to play around with the code where you see TimeUnit.Months