Please see Elvis in this clip , what technique Elvis is using to create this raspy and powerful tone? Thanks!
I'm pretty sure that effect is vocal fry. That's what creates the raspy tone at least. To learn more about it, this tutorial is an absolute SLOG to get through because the guy keeps talking about nothing, but buried within is some good information. A lot of his videos have good info but my goodness does he like to talk!
The other thing Elvis does, he uses vocal cries. These are the high pitch whimpers he embellishes end notes with. At the time stamp you provide, the lines: When I read your loving letter, Then my heart began to sing... listen to how he whines on "letter" and "sing". Mixing fry, which is in low chest and very little airflow, and whines which are higher and more nasally is quite fun to listen to. They're almost the opposite of each other, and Elvis does them particularly well.
Another singer who does this is Pink. In general she sings with rasp, but you can really hear the push and pull of fry and cry in her song Glitter in the Air, particularly in the chorus from 0:48.