How do I scan for viruses on my Mac book pro?

Since there are no viruses that affect macOS, the only things that allege the ability to "scan" for them are either scams, or malware in and of themselves.

If you are having trouble with your Mac, please describe what's wrong in as much detail as you are willing to provide.

You don’t need to scan for viruses because there are no known viruses for the Mac that can infect your Mac by themselves. Malware these days needs to trick the user (known as phishing) into installing it. Use common sense and think before you click on something. macOS itself has detection and protection built in.

Third party anti-virus software is basically useless on a Mac as they usually detect Windows viruses and can slow down or interfere with the operation of your Mac.