Assuming you already enrolled in a developer license program and have an apple id.
Follow these steps:
open up file name with extension .xcworkspace
Navigate through Project Name > Targets > General
1. Change the display name of the app, this is what the name of the app that you want the users to see in their devices.
2. Provide an unique bundle identifier of the
100% FREE: Do-it-yourself with all the free tecnology and free tutorial/support site
Only $199: Hire an agency and watch them to do it all. Order here