What if I visited Malicious site from my Mac book Safari browser? How can I confirm whether my Mac book is safe or not?

Merely loading a website, malicious or not, has literally no effect on a Mac.

Zero. None.

Just close the page and forget you ever saw it. Delete Safari's History if you want: Clear your browsing history in Safari on Mac - Apple Support. Then, not even your Mac will remember visiting that site.

Do not install anything in response to that website. Downloading and installing things is what gets people into trouble, not visiting malicious websites.

dhaval252 wrote:

What if I visited Malicious site from my Mac book Safari browser? How can I confirm whether my Mac book is safe or not?

You cannot reasonably confirm a lack of a breach. Proving a negative is… difficult. But to be very blunt, you’re not compromised, and you are very likely not with the cost and effort involved in such a compromise. You’re just not. And if you truly are worth targeting, then you really, really, really need a better source of security information than this forum.

If a website could access and could scan a computer, there’d be chaos. Yes, there have been a few of these breaches. Rare. But they’d happen. Watering hole breaches, for instance. If the perpetrators were broadly targeting, we’d we’d hear about these cases.

Here’s a watering hole attack targeted against Mac users from last year:

… https://blog.google/threat-analysis-group/analyzing-watering-hole-campaign-using-macos-exploits/

Now what can you do? Backups. Preferably deep backups. Preferably rotating. Better password security. You can operate from a non-admin user too, to make the exploitation yet mire difficult. Stay current on macOS. Add two-factor authentication. Robust and unique passwords. Keychain or another password manager. The usual suggestions.

Not knowing manufacturing year or OSX Version., if you have any Internet connection, I would boot into recovery, Run disk utility app, and reinstall my OSX software.