I am trying with putty below command and its working
php artisan horizon
But if I close ssh (putty) this command automatically shut down.
I want to run this command always in the background.
You have some options for run some process in background :
in your case the first option is the best.
Try with & at the end of the command to put the process background.
php artisan horizon &
fg to get the last background command into the foreground and Ctrl+c to terminate it.