How can users find out or download what information Apple has about them?
Apple does in fact provide such a service, although it's not yet an instant1  download scenario like what is offered by Facebook and Google. To access the information Apple currently has about you, follow these steps:


Go to: https://www.apple.com/privacy/contact/
A Privacy Questions page will open
Select the Privacy issues option from the drop-down list
A form will appear with six mandatory fields
Enter your region, name and email address (Note: Apple will use this info later to help it match your identity, so you will need to answer these truthfully)
Enter something appropriate for the subject
In the Comments field enter a small description of what you're after. You do not need to go into any great detail - simply request a copy of any personal information they have and a history of anything you've purchased/downloaded from Apple services
Click on the blue Submit button
A Thank You message will appear
Apple will initially respond by requesting further information from you (e.g. your street address, phone number and details about Apple products you own)
After verifying your identity Apple will send you a .zip file containing your information


NOTE: Be patient - your request is likely to take anywhere from a few days to a couple of weeks.

1 It's not necessarily an instant service from Facebook or Google, but you'd typically be able to download the data within a few hours. While Apple is moving towards a similar self-serve model, it's not currently ready in most parts of the world, although it will be available in Europe before the end of May 2018.



Below are some related articles which may be of interest:


I downloaded all my Facebook data. This is what I learned.
How to download your Google data and what you'll find.
Apple took 8 days to give me the data it had collected on me. It was eye opening.


NOTE: I have no affiliation with USA Today or the author (Jefferson Graham) of the above articles.