How to get receipts from Apple?

For hardware and Apple Store purchases:

Receipts are listed in your Orders overview, for the last 18 months. See the shopping bag in the upper right corner on every webpage of the Apple site.

For older purchases, you will need the order number to look it up. Please save your receipts from Apple.

For content and apps:

View your purchase history for the App Store, iTunes Store, and other Apple media services - Apple Support

You should be able to scroll through the years descending.