change security question

Try using Apple's iForgot service.

If it says they don't have sufficient information, you need to set up two-factor authentication or contact Apple's Account Security team. To reach them, click here or here and pick a method; if you can't use any of those listed, choose one from this link.

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To change security questions: First, you need to know your apple id email and password. Without that this won't work.  Go to iPhone or iPad, go to settings > mail > accounts > add account> choose icloud> enter apple id email and password. It will then ask you to enable 2 factor? Choose 2 factor. After that it will use your phone number to verify you and will no longer use security questions. (Note you need to choose iCloud even if its a third party email.)