There are a few things you need in order to record yourself singing on your iPhone. The first is an iPhone microphone. The second is an app that will allow you to sing along with music. The third is a song or audio file. Finally, you will need some headphones in order to hear yourself singing. To start recording, open the microphone app and select the song or audio file you want to sing along with. Once the song or audio file has been selected, press the record button and wait for the recording to start. To stop the recording, simply press the stop button again.