If you don't want to create an ‌Apple ID‌ during the device setup process, you can do it later on the ‌iPhone‌ or ‌iPad‌ through the Settings app. Open the Settings app.

You can also create an Apple ID using the Mac App Store if you prefer. Open up the Mac App Store. Click on the "Sign In" button at the bottom of the window. Choose the "Create Apple ID" option.