Xcode - Change Company Name and Username

go to System preferences -> users and groups -> click on your username

On that page there should be a button saying Open... click that and change that record in your contacts. When you create a new class it should get the information from that record!

For changing author name in Xcode 6, just go to User & Groups in system preferences, right click current user (make sure permission is unlocked), select Advanced Options, change the "Full name" section.

For the User Name:

Open up the address book and go to your user account, and edit your name (the large, bold line at the top). (Address Book is by default the first app in your Applications folder.)

If you don't know which contact is your user account: Open up System Preferences. Go to Users & Groups (in the System row); your user account should already be selected. Click on the "Open..." button for the Address Book Card.

Changing your name in the Address Book won't change any already-created files; it will only affect new files that you create.

For the Company Name:

In Xcode 4, open up your project. Select the top-most item in the Project Navigator (MyProjectName, 1 target, iOS SDK 4.3 -- or whatever). Open up the file inspector (View->Utilities). In the Project Document section, you should see an "Organization" line. Edit that, and new files that you create will display the new organization name. This is a project setting, hence you'll have to do it for every project.

For new projects that you create, the Organization Name will be whatever the value was on the previously open project. (You can edit it when creating the new project.)