Can i distribute my APNs certificate and key to many people and all those peoples servers can send notification to my iOS app on device. I have the device token etc. I need to know is there any limitations on this process
You need to generate .pem certificate from your APNs for production as well as development. You can find steps to do so here in this thread and here in Apple Docs
Once you have valid .pem certificate you can use it from any server . There is no limitation in Apple Docs for using this but ofcourse , that pem certificate will work for sending notification to your app only .
Hope this helps.