I can't believe a moderator for a group dismisses your question without understanding it. I've been looking for this all over the Internet as well and finally figured it out. I have the Note 9 but I bet it's the same for all Samsung phones with latest software. Note 8, S9, S9+. Etc
The issue is that when you go to messages /settings /more settings/text messages and toggle to get delivery report, the messages app not only gives you visual "delivered " message but also an annoying pop up and SOUND. I only want the "delivered " visual cue and can live with the pop-up but the sound was terrible.
To disable the delivery reports sound for Note 9 and Note 8, in the Samsung messages app
Go to Settings /Notification /
Under categories go to general notifications (not new messages)
It should be toggled on, not touch it to see the options and from there under notification style pick SILENT. Now you will get the "delivered" word by the message without annoying sound and pop-up every time you send a text.
I wrote this with as many keywords so others can find it since I've been looking for a few days and found no help Googling it. Hope it helps others.
Ridiculous that something simple as this is so hidden. South Korean companies don't know what user interface means. Just copy copy copy....