Where do I set my company name?

By default, Xcode inserts a company name something similar to the following in all new source files (.m .h etc):

Copyright (c) 2009 MyCompanyName. All rights reserved.

Changing this reference is as simple as entering the following from within a terminal window, replacing “YourNameHere” with the text you prefer. Also, make sure this is all entered on one line in the terminal.

defaults write com.apple.Xcode PBXCustomTemplateMacroDefinitions '{ORGANIZATIONNAME="YourNameHere";}'

OR

you could even go to ~/Library/Preferences and double-click com.apple.Xcode.plist and use the handy-dandy plist editor to set this and a whole bunch of other interesting defaults not covered by the Xcode or IB preference panels.

OR

@slf answer on this question shows an improved way to achieve this in Xcode 4 (Pasted below)

in the navigation pane (far left side), select the project (top item).

Expand the Utilities pane (at window top-right, far right button in the 3-button "View" group).

In the "Project Document" section is the "Organization" text field (File Inspection view, second section from top).

in Xcode 4 GM seed:

in the navigation pane (far left side), select the project (top item).

Expand the Utilities pane (at window top-right, far right button in the 3-button "View" group).

In the "Project Document" section is the "Organization" text field (File Inspection view, second section from top).

In Xcode 7.3 (edit: till 13.3.1) just select top project file and Look in Utilities on Left pane