This is an recommendation we have found somewhere: "Have the 3rd celebration send the "proof of service" or the IRS will state they perceived an dull pouch even if we uncover the approved mail receipt."

How can we secure an undoubted explanation which we mailed the specific content accompanied with specific papers to the IRS as well as not usually an dull envelope?

The usually approach we know of to infer promulgation the specific content is the telegraph / wire. Is there anything some-more convenient?

Thanks.