Install antivirus on macOS
Sometimes stumbling into a bad link in your email, or on the Internet, makes trouble for macOS. And a Virus Scanner -or- Anti malware program may help…
For security, Apple ‘inspects’ programs before offering them on their ‘App Store’.
To use the App Store, Go to the Apple Menu > App store
Upper left side, go to 'Featured'
Look to the upper right… Click in the 'Search' field…
And type the word 'virus'… press 'return'
You may get Bit Defender… Which is free…
… In any case, click ‘Get’,
type in your Apple ID, and password…
Once it is downloaded Open Bit Defender from the Applications folder, or click Open in the App store…
Click ’Update Now' to Get an up-to-date ‘list’ of malware, called signatures, they’re like ‘fingerprints’ of known offenders.
To get scanning,
Click the level of scanning… Grant Access… then Allow Access, to each area
after the 'Scanning’ begins, it may take hours to scan your Mac.
The software shows files that may have Threats, You may 'Reveal in Finder', then drag to the Trash, and Empty Trash.