The difference between “customizing” and “personalizing” can be confusing. Do you customize something to personalize it, or personalize something to customize it?
The first is true. You customize something so it’s personalized.
One of the reasons these terms aren’t always distinguishable is because personalization is relatively new in some areas.
Personalized medicine is new. It uses genetics to tailor a treatment that has been customized for each patient.
Personalized learning has been around for a long time. From the teacher’s perspective, personalization means designing learning experiences that provide students with choices they can make depending on their own needs.