Import date field with feeds
I've struggled with this question today, and because i didn't found any clear answer here's the method with drupal 8.7:


go to your node type structure, and select the display of your field (for example : DD-MM-YYYY)
go back to the feeds mapping, remove your date entry.
add a new entry for the date, or rebuild the entire mapping if you can't change the order of your csv.
clear the cache
the date work now with your new format