How to set format of date in date field
Path: Home » Administration » Configuration » Regional and language
Or 
Path : admin/config/regional/settings

In the above path there will be tab called 'format' where you can create your own custom format where format string is F j, Y, g:i a e.
 Now you can change the date format of the field from the manage displays tab of the admin/structure/types path.
 In the respective field you will have settings options where you can set your custom date format