Anna has purchased Bitcoin Cash by mistake. The site Bitcoin.com tried to trick people in the past by giving the real Bitcoin a wrong name on their site. They referred to it as Bitcoin Core. When you pressed on the buy button, the site would set up your purchase for Bitcoin Cash just like you can see on the screenshot. Bitcoin Cash gets automatically selected. People who purchase Bitcoin for the first time got tricked this way because they thought they were purchasing the real Bitcoin and not Bitcoin Cash which is an altcoin.
That's what happened to Anna. She now owns Bitcoin Cash that she accidently sent to her Bitcoin non-custodial wallet. Luckily for her, she has full control of the coins because her wallet allows her to see and extract private keys for its addresses. What does she need to do with the private key of the address the coins were sent to?
As I wrote earlier, she just can check the purse's balance on the site for example blockchain.com. And since she has a private key, it can at any time import a private key to any software wallet and she will see their coins there and will be able to send them where he wants.