$14.99 payment to Apple iPhone

Apparently I authorised a payment for (What - I don't Know) and an amount of $14.99 payment is shown on my bank statement.

How do I find out "What I purchased" -

This is a first for me I'm almost 80.

Can anyone "Shed" any light on this matter and "How do I seek a refund or even get told/advise what the heck I Purchased"

It is totally 'IN ERROR'