We don't need to create simulator for Mac; it already comes with Xcode under developer tools.
To launch simulator perform following steps:
Step 1: Check list of available Xcode devices using below command
$ instruments -s devices[This will return device uuid and name]
Step 2: Start Appium Server
Step 3: Start Inspector Session
Step 4: Enter deviceName, Udid, App Path, automationName, platformName
Step 5: Click on Start Session