Apologize letter format English?

The format of English apology letter is as follows:

Fan Wen:

Dear Mr. Robert.

I want to apologize for the delay in shipping your order. Due to the excessive demand last month, it seems impossible for us to process all orders in time. However, we sent your order earlier this morning, and we believe you will receive it tomorrow.

Please accept our sincere apologies again for any inconvenience we have caused you. Thank you very much for your consideration.

You are sincere.

NKC company

General sentence pattern:

I want to apologize for ~.

I'm sorry about.

Please accept my sincere apology.

Please accept my sincere apology.

I'm really sorry for what I said/did, but please believe that I didn't mean to insult you.

I'm really sorry for what I said/did. But please believe that I didn't mean to insult you.

There should be no misunderstanding between us.

Don't let there be even a little misunderstanding between us.

Please forgive my improper use of words.

Please forgive my improper use of words.