print list of itunes purchases

See your purchase history in the App Store or iTunes Store - Apple Support

Once you have accessed the list, I recommend taking a screenshot of them on your Mac by using the Grab application, or using the command Shift+Command+4, or taking a screenshot on your apple device by clicking the home button and power at the same time, or if on an iPhone X clicking the power button and volume button at the same time.

After this has been done, you can open the screenshot and print it out.

Hope I helped!