If you already have an employment contract then that covers it, a salary increase in these times is very welcome, you are obviously valued, it would be usual to receive something even an e-mail from H.R. but it will be shown on your salary slip anyway, accept it with thanks and move on.
I dont think the "You should be glad to get it, be quiet and move on" attitude is very helpful to the OP. Confirmation in writing of a change in salary is a basic requirement.
... it would be usual to receive something even an e-mail from H.R. ....