Why do some messages show delivered and some don't

[Pappy1007]

Can anyone tell me why some of my messages show delivered and read and other ones don't? Any help would be greatly appreciated!

[KnightRiderRalph]

It's RCS messaging. It could be because you have RCS enabled but maybe others don't or don't have that feature because of their carrier. 

[Pappy1007]

My family is all together with AT&T. All Samsung phones. I can see the delivered and read with our granddaughter but not the other 5

[kmb1]

Also, Google messages has options you can turn off in settings so senders can't tell whether you've read the message, or not.

[SED70]

How do you enable RCS MESSAGING ON A S21..I have tried Google messages also...neither app with show when read..only delivered...any help would be greatly appreciated since I spent an hour on the phone with Samsung and they say its my Carrier....spent 45 minutes with my Carrier...they say its an app problem....I have been using Samsung messages for years and now it hasn't worked for the last 2 weeks.HELP!! TIA