Answer 1

class = "Submit" adds the class Submit to that button enabling changes to be made to it through css. For more on classes:

https://www.w3schools.com/html/html_classes.asp

value = "Submit" changes the text on the button, so value = "Hello" would change the text on the button to be "Hello".

The reason both look the same us because by default the value of a button is "Submit" so even if no value is declared that is what the text on the button will be.