Finder's "Date Added" vs. "Date Created"
Put simply:


Date Added refers to when the item was added to the directory in question.
Date Created refers to when the item was actually created.


The best way to explain this is to use the example of a screenshot. If you took a screenshot at exactly 12:05pm on 1 March 2018 it'll have a Date Created of 1 March 2018 at 12:05 pm. 1

Now, let's say you move that screenshot at 8:00am on 10 April 2018 to another folder (e.g. you move it from the desktop to your Documents folder), then the Date Created is still the same, but the Date Added will show 10 April 2018 at 8:00 am. 1

Depending on what the item's history is, it can have the exact same date and time in both columns.

1. Note the actual format will depend on your macOS configuration