How to create Bundle Identifier and Provisioning Profile for new XCode iOS project?
Assuming you already have a valid certificate in your Apple Developer Center.
Go to Identifiers > App IDs > click + button.
AppID should follow this format : com.myCompany.myAppName
Other configuration settings can be varied.
Click continue to finish this step.
After created an AppID successfully, go to "Provisioning Profiles" > click + button.
Choose "iOS App Development" for development purpose and choose the AppID we just created from previous step.
3rd step allows you to choose the Certificate and you will be able to download the Provisioning Profile after that.
Summary
An iOS app must have an AppID (which will be used as Bundle Identifier)
AppID and a certificate is required to generate Provisioning profile which will help to install the iOS app in the real device during development stage.