Does assignment submission happen automatically when a student submits or is there a delay?

[AHamm]

Unfortunately, we have a student who says they submitted work which we find out subsequently was not submitted. I am trying to help the student understand that when submitted, it shows the date and time for submission. However, the student indicates that the submissions occur and then is there a delay. 

Is there a delay or something that requires a teacher's action when something is submitted before it shows the time/date stamp or does that time/date stamp get generated automatically with no delay. 

Thanks! 

[CanvasUser61524]

Canvas will not automatically give you the grade. I takes time to receive the grade