JMeter neither can check iOS device performance nor assess the application performance. If this is what you're looking for - check out
XCode Instruments
What JMeter can do is to simulate hundreds/thousands mobile applications which are concurrently accessing the backend, to wit you will be load testing the backend
In this case you can use JMeter, choose relevant
Samplers which support
network protocols used by your iOS application and configure them accordingly to simulate network footprint representing the real user using the iOS application.
- Start JMeter's HTTP(S) Test Script Recorder
- Install JMeter's certificate on the iOS device (or simulator), the file is called ApacheJMeterTemporaryRootCA.crt and it's generated in "bin" folder of your JMeter installation when you start the HTTP(S) Test Script Recorder
- Enable Full Trust for the certificate
- Configure your iOS device to use the machine where JMeter is running as the proxy
- You should be able to record