I’m located in CA (Bay Area) my HCRE is scheduled to arrive from Jake in January ,
Is there a mileage number before the emission system will activate ?
The emissions system (systems) are active when they should be. For example even with the engine off the fuel vapor recovery system is operational.
Then when you start the engine the various emissions systems like fuel/air metering, exhaust gas processing, and dealing with any vapor the gasoline vapor recovery system trapped all are active and remain active as long as the engine is running.
It might be necessary to drive the vehicle long enough to have all the readiness monitors tested and set to complete.
I never bought a car out of state when I lived in CA. I bought a number of new cars and one used car. The new cars were not required to be emission compliance tested for IIRC 6 years. The used car seller (a dealer) was required to confirm the car was emissions compliant before it could sell the car. In all cases I never had to worry about the readiness monitors being set to complete for any new car and the one used car only every other year, IIRC.
As long as the car is certified 50 state emission compliant or certified for sale in CA you should be ok.