why do we need python extension if python already present in our PC or if visual code extension is present then there is no need for installing the software in our pc.
Sorry, I don’t understand what you are talking about.
When you say “python extension”, do you mean “.py” at the end of file names? What is “visual code extension”?
If by “visual code” you mean “visual studio code”, then technically you don’t need the python extension for it, you can just use vscode as a simple text editor, and do all the linting, debugging, unit-testing and environment management in the terminal.
The extension just integrates those tools with the vscode GUI and provides some extra nice to have things while editing like auto-completion, but you don’t need any of that, it is just nice to have.