Microsoft visual code is installed on your laptop, but the line numbers are not displayed so you can know which line you are in while writing code and make your work easy and find yourself.
Follow the steps
Select Tools > Options from the navigation bar.
Expand the Text Editor node,
Then choose either your current language or All Languages to enable line numbers in all languages.
(Alternatively, put line number into the search box and choose Turn line numbers on or off from the list of options.)
Check the box for Line numbers.