Here's the correct way to say or write this:
We would like to confirm that the goods were delilvered on 04 Aug.
Here's another way:
We would like to confirm that the goods have been delivered.
With the present perfect, we don't use a specific date, as this is finished time in the past. We use the present perfect to speak of time up until now, generally speaking.
Post follow-up questions if you have any.