Can we use SVG element without height and width attributes in HTML???

Answer 1

Yes, default width and height are 300px and 150px

Answer 2

Actually you shouldn't use the width and height attribute.

Use CSS to set width and height of SVG elements depending on screen size.

Use viewBox attributes to set the view box of SVG

My video tutorial about viewBox:
https://youtu.be/NwhRS6VUwVU