Do I need to add Anti Virus to my new Mac or is it secure
no system is more secure than the one operating it let it be
if you expect a third party system to stop you from allowing downloaded apps from having administrator rights and if you type in your appleID/ username and password and pin code for your credit card then the protection software would have to be pretty invasive to be able to save you from yourself.
No Anti-Virus software or so-called “cleaning” apps are needed or recommended for Mac OS. They can conflict with Mac's own built-in security. At best they will slow your Mac by using unnecessary resources and at worst will bork your entire system.
It is secure out of the box. Adding any third-party AV will likely make it less secure.
Your brain is by far the best AV software, no matter what OS you use.
BobTheFisherman already posted a link to a very good article on how to use your brain effectively.
This is also handy: How to install adware - Apple Community
Depending upon your web browsing, and file downloading from non-vendor sites behavior, you may need to incorporate an ad/malware checking application. Many of us recommend (and use) Malwarebytes for Mac. It provides a 14-day full trial of its realtime features, and then reverts to a free to use utility. There is an optional subscription if you want to reinstate the full realtime features. Personally, I don't.
Malwarebytes will check for Malware and offer to remove any that it finds. It is not an anti-virus tool, of which there is no need on the Mac.
Do I need to add Anti Virus to my new Mac or is it secure
