"is paid" vs "has been paid"

What is the difference between the above passive forms? When we use “the goods have been paid” and when “the goods are paid”?
Thank you in advance!

You can never say “the goods have been paid” OR “the goods are paid”. Both are wrong, because no one is giving money to the goods. We give money to someone else FOR the goods. You pay someone for something you are buying. You don’t pay the thing you are buying.

So, the correct way to say these is:

The goods have been paid for.
This means we have finished paying for the goods, and we don’t need to pay again.

The goods are paid for.
This can mean one of two things: (1) that someone pays for the goods on a regular basis, such as every week, every month, etc., or (2) that we have finished paying for the goods.

In meaning (2), the word “paid” is used as an adjective, not as a verb.

Of course, you can say these:

The invoice is paid (in full).
The invoice has been paid.