I want to localize my app, and I add French and Spanish to the target properties other than English
You need to add in your Info Project the localizations (I can't add image sorry).
And next you need to create a new file in your project named "Localizable.strings" and Localize this file in your identity menu.
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If you go to the "Info" pane of your project, you'll see a panel that shows your Deployment Target, Configurations and also the current localizations that you support (including a checkmark for "Use Base Internationalization"). Base Internationalization, b.t.w., allows you to have a single storyboard file that has different string files populating the string fields in the storyboard. It works for iOS 6 and newer.
When you start, it might look like this:
Here I've added Hindi as a language possibility:
And when you're done, you have the checkbox to choose from:
Just click on your project in "Info" panel , where you can see "Localizations" and add the languages you want.