I tried to erase the width and height in svg while using rect with height and with what's the difference

Answer 1

if you don't fill any of the value properly your svg won't take proper effect as it the svg tag is like describing that i need some space with these height and width and rect value will say that in my svg space i need my rectangle to be of these height and width and style

Answer 2

Rectangle - x and y points to the starting position on the screen. Top left corner of rectangle is the starting point. The height and width of the rectangle declares the size of the rectangle.
Height and width in svg element is the maximum height and width the rectangle can use.